diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00e897f..4a82435 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 ### Added
+- Units can have comments, to make it easier to distinguish between units of
+  same type within an instrument. These comments are also shown when choosing
+  the send target. ([#114][i114])
 - A toggle button for copying non-unique patterns before editing. When enabled
   and if the pattern is used in multiple places, the pattern is copied first.
   ([#77][i77])
@@ -232,6 +235,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [i77]: https://github.com/vsariola/sointu/issues/77
 [i94]: https://github.com/vsariola/sointu/issues/94
 [i112]: https://github.com/vsariola/sointu/issues/112
+[i114]: https://github.com/vsariola/sointu/issues/114
 [i116]: https://github.com/vsariola/sointu/issues/116
 [i120]: https://github.com/vsariola/sointu/issues/120
 [i121]: https://github.com/vsariola/sointu/issues/121
diff --git a/patch.go b/patch.go
index 549572e..6b3c79d 100644
--- a/patch.go
+++ b/patch.go
@@ -49,6 +49,11 @@ type (
 		// Disabled is a flag that can be set to true to disable the unit.
 		// Disabled units are considered to be not present in the patch.
 		Disabled bool `yaml:",omitempty"`
+
+		// Comment is a free-form comment about the unit that can be displayed
+		// instead of/besides the type of the unit in the GUI, to make it easier
+		// to track what the unit is doing & to make it easier to target sends.
+		Comment string `yaml:",omitempty"`
 	}
 
 	// UnitParameter documents one parameter that an unit takes
@@ -291,7 +296,7 @@ func (u *Unit) Copy() Unit {
 	}
 	varArgs := make([]int, len(u.VarArgs))
 	copy(varArgs, u.VarArgs)
-	return Unit{Type: u.Type, Parameters: parameters, VarArgs: varArgs, ID: u.ID, Disabled: u.Disabled}
+	return Unit{Type: u.Type, Parameters: parameters, VarArgs: varArgs, ID: u.ID, Disabled: u.Disabled, Comment: u.Comment}
 }
 
 // StackChange returns how this unit will affect the signal stack. "pop" and
diff --git a/tracker/gioui/instrument_editor.go b/tracker/gioui/instrument_editor.go
index 7241927..966a5c7 100644
--- a/tracker/gioui/instrument_editor.go
+++ b/tracker/gioui/instrument_editor.go
@@ -393,7 +393,8 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 	count := intMin(ie.unitDragList.TrackerList.Count(), 256)
 
 	element := func(gtx C, i int) D {
-		gtx.Constraints = layout.Exact(image.Pt(gtx.Dp(unit.Dp(120)), gtx.Dp(unit.Dp(20))))
+		gtx.Constraints.Max.Y = gtx.Dp(20)
+		gtx.Constraints.Min.Y = gtx.Constraints.Max.Y
 		if i < 0 || i > 255 {
 			return layout.Dimensions{Size: gtx.Constraints.Min}
 		}
@@ -418,7 +419,7 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 		stackLabel := LabelStyle{Text: stackText, ShadeColor: black, Color: mediumEmphasisTextColor, Font: labelDefaultFont, FontSize: unit.Sp(12), Shaper: t.Theme.Shaper}
 		rightMargin := layout.Inset{Right: unit.Dp(10)}
 		return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
-			layout.Flexed(1, func(gtx C) D {
+			layout.Rigid(func(gtx C) D {
 				if i == ie.unitDragList.TrackerList.Selected() {
 					editor := material.Editor(t.Theme, ie.searchEditor, "---")
 					editor.Color = color
@@ -473,6 +474,11 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 					return unitNameLabel.Layout(gtx)
 				}
 			}),
+			layout.Flexed(1, func(gtx C) D {
+				unitNameLabel := LabelStyle{Text: u.Comment, ShadeColor: black, Color: mediumEmphasisTextColor, Font: f, FontSize: unit.Sp(12), Shaper: t.Theme.Shaper}
+				inset := layout.Inset{Left: unit.Dp(5)}
+				return inset.Layout(gtx, unitNameLabel.Layout)
+			}),
 			layout.Rigid(func(gtx C) D {
 				return rightMargin.Layout(gtx, stackLabel.Layout)
 			}),
@@ -517,7 +523,7 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 		return layout.Stack{Alignment: layout.SE}.Layout(gtx,
 			layout.Expanded(func(gtx C) D {
 				defer clip.Rect(image.Rect(0, 0, gtx.Constraints.Max.X, gtx.Constraints.Max.Y)).Push(gtx.Ops).Pop()
-				gtx.Constraints = layout.Exact(image.Pt(gtx.Dp(unit.Dp(120)), gtx.Constraints.Max.Y))
+				gtx.Constraints = layout.Exact(image.Pt(gtx.Dp(140), gtx.Constraints.Max.Y))
 				dims := unitList.Layout(gtx)
 				unitList.LayoutScrollBar(gtx)
 				return dims
diff --git a/tracker/gioui/unit_editor.go b/tracker/gioui/unit_editor.go
index b39bfc1..2738346 100644
--- a/tracker/gioui/unit_editor.go
+++ b/tracker/gioui/unit_editor.go
@@ -32,7 +32,9 @@ type UnitEditor struct {
 	ClearUnitBtn   *ActionClickable
 	DisableUnitBtn *BoolClickable
 	SelectTypeBtn  *widget.Clickable
+	commentEditor  *widget.Editor
 	caser          cases.Caser
+	commentFilters []event.Filter
 
 	copyHint        string
 	disableUnitHint string
@@ -46,10 +48,19 @@ func NewUnitEditor(m *tracker.Model) *UnitEditor {
 		DisableUnitBtn: NewBoolClickable(m.UnitDisabled().Bool()),
 		CopyUnitBtn:    new(TipClickable),
 		SelectTypeBtn:  new(widget.Clickable),
+		commentEditor:  &widget.Editor{SingleLine: true, Submit: true, MaxLen: 16},
 		sliderList:     NewDragList(m.Params().List(), layout.Vertical),
 		searchList:     NewDragList(m.SearchResults().List(), layout.Vertical),
 	}
 	ret.caser = cases.Title(language.English)
+	for k, a := range keyBindingMap {
+		if len(a) < 4 || a[:4] != "Note" {
+			continue
+		}
+		ret.commentFilters = append(ret.commentFilters, key.Filter{Name: k.Name, Required: k.Modifiers, Focus: ret.commentEditor})
+	}
+	ret.commentFilters = append(ret.commentFilters, key.Filter{Name: key.NameSpace, Focus: ret.commentEditor})
+	ret.commentFilters = append(ret.commentFilters, key.Filter{Name: key.NameEscape, Focus: ret.commentEditor})
 	ret.copyHint = makeHint("Copy unit", " (%s)", "Copy")
 	ret.disableUnitHint = makeHint("Disable unit", " (%s)", "UnitDisabledToggle")
 	ret.enableUnitHint = makeHint("Enable unit", " (%s)", "UnitDisabledToggle")
@@ -139,6 +150,11 @@ func (pe *UnitEditor) layoutFooter(gtx C, t *Tracker) D {
 		text = pe.caser.String(text)
 	}
 	hintText := Label(text, white, t.Theme.Shaper)
+	commentStyle := material.Editor(t.Theme, pe.commentEditor, "---")
+	commentStyle.Font = labelDefaultFont
+	commentStyle.TextSize = labelDefaultFontSize
+	commentStyle.Color = mediumEmphasisTextColor
+	commentStyle.HintColor = mediumEmphasisTextColor
 	return layout.Flex{Axis: layout.Horizontal, Alignment: layout.Middle}.Layout(gtx,
 		layout.Rigid(deleteUnitBtnStyle.Layout),
 		layout.Rigid(copyUnitBtnStyle.Layout),
@@ -151,7 +167,39 @@ func (pe *UnitEditor) layoutFooter(gtx C, t *Tracker) D {
 			}
 			return D{Size: image.Pt(gtx.Dp(unit.Dp(48)), dims.Size.Y)}
 		}),
-		layout.Flexed(1, hintText),
+		layout.Rigid(func(gtx C) D {
+			gtx.Constraints.Min.X = gtx.Dp(120)
+			return hintText(gtx)
+		}),
+		layout.Flexed(1, func(gtx C) D {
+			s := t.UnitComment().String()
+			if pe.commentEditor.Text() != s.Value() {
+				pe.commentEditor.SetText(s.Value())
+			}
+			for {
+				ev, ok := pe.commentEditor.Update(gtx)
+				if !ok {
+					break
+				}
+				_, ok = ev.(widget.SubmitEvent)
+				if ok {
+					t.InstrumentEditor.Focus()
+					continue
+				}
+			}
+			for {
+				event, ok := gtx.Event(pe.commentFilters...)
+				if !ok {
+					break
+				}
+				if e, ok := event.(key.Event); ok && e.State == key.Press && e.Name == key.NameEscape {
+					t.InstrumentEditor.Focus()
+				}
+			}
+			ret := commentStyle.Layout(gtx)
+			s.Set(commentStyle.Editor.Text())
+			return ret
+		}),
 	)
 }
 
@@ -317,11 +365,11 @@ func (p ParameterStyle) Layout(gtx C) D {
 					targetInstrument := p.tracker.Instrument(targetI)
 					instrName = targetInstrument.Name
 					units := targetInstrument.Units
-					unitName = fmt.Sprintf("%v: %v", targetU, units[targetU].Type)
+					unitName = fmt.Sprintf("%d: %s %s", targetU, units[targetU].Type, units[targetU].Comment)
 					unitItems = make([]MenuItem, len(units))
 					for j, unit := range units {
 						id := unit.ID
-						unitItems[j].Text = fmt.Sprintf("%v: %v", j, unit.Type)
+						unitItems[j].Text = fmt.Sprintf("%d: %s %s", j, unit.Type, unit.Comment)
 						unitItems[j].IconBytes = icons.NavigationChevronRight
 						unitItems[j].Doer = tracker.Allow(func() {
 							tracker.Int{IntData: p.w.Parameter}.Set(id)
@@ -333,7 +381,7 @@ func (p ParameterStyle) Layout(gtx C) D {
 					layout.Rigid(p.tracker.layoutMenu(gtx, instrName, &p.w.instrBtn, &p.w.instrMenu, unit.Dp(200),
 						instrItems...,
 					)),
-					layout.Rigid(p.tracker.layoutMenu(gtx, unitName, &p.w.unitBtn, &p.w.unitMenu, unit.Dp(200),
+					layout.Rigid(p.tracker.layoutMenu(gtx, unitName, &p.w.unitBtn, &p.w.unitMenu, unit.Dp(240),
 						unitItems...,
 					)),
 				)
diff --git a/tracker/list.go b/tracker/list.go
index 2a7db6d..8ba5731 100644
--- a/tracker/list.go
+++ b/tracker/list.go
@@ -33,7 +33,7 @@ type (
 	}
 
 	UnitListItem struct {
-		Type                               string
+		Type, Comment                      string
 		Disabled                           bool
 		StackNeed, StackBefore, StackAfter int
 	}
@@ -332,6 +332,7 @@ func (v *Units) Iterate(yield UnitYieldFunc) {
 		stackAfter := stackBefore + unit.StackChange()
 		if !yield(UnitListItem{
 			Type:        unit.Type,
+			Comment:     unit.Comment,
 			Disabled:    unit.Disabled,
 			StackNeed:   unit.StackNeed(),
 			StackBefore: stackBefore,
diff --git a/tracker/string.go b/tracker/string.go
index 55ee5f9..34e5b0c 100644
--- a/tracker/string.go
+++ b/tracker/string.go
@@ -15,6 +15,7 @@ type (
 	InstrumentName    Model
 	InstrumentComment Model
 	UnitSearch        Model
+	UnitComment       Model
 )
 
 func (v String) Set(value string) {
@@ -30,6 +31,7 @@ func (m *Model) FilePath() *FilePath                   { return (*FilePath)(m) }
 func (m *Model) InstrumentName() *InstrumentName       { return (*InstrumentName)(m) }
 func (m *Model) InstrumentComment() *InstrumentComment { return (*InstrumentComment)(m) }
 func (m *Model) UnitSearch() *UnitSearch               { return (*UnitSearch)(m) }
+func (m *Model) UnitComment() *UnitComment             { return (*UnitComment)(m) }
 
 // FilePathString
 
@@ -108,3 +110,26 @@ func (v *InstrumentComment) setValue(value string) {
 func (v *InstrumentComment) change(kind string) func() {
 	return (*Model)(v).change("InstrumentComment."+kind, PatchChange, MinorChange)
 }
+
+// UnitComment
+
+func (v *UnitComment) String() String { return String{v} }
+func (v *UnitComment) Value() string {
+	if v.d.InstrIndex < 0 || v.d.InstrIndex >= len(v.d.Song.Patch) ||
+		v.d.UnitIndex < 0 || v.d.UnitIndex >= len(v.d.Song.Patch[v.d.InstrIndex].Units) {
+		return ""
+	}
+	return v.d.Song.Patch[v.d.InstrIndex].Units[v.d.UnitIndex].Comment
+}
+
+func (v *UnitComment) setValue(value string) {
+	if v.d.InstrIndex < 0 || v.d.InstrIndex >= len(v.d.Song.Patch) ||
+		v.d.UnitIndex < 0 || v.d.UnitIndex >= len(v.d.Song.Patch[v.d.InstrIndex].Units) {
+		return
+	}
+	v.d.Song.Patch[v.d.InstrIndex].Units[v.d.UnitIndex].Comment = value
+}
+
+func (v *UnitComment) change(kind string) func() {
+	return (*Model)(v).change("UnitComment."+kind, PatchChange, MinorChange)
+}