diff --git a/bar_option.go b/bar_option.go
index 3a1c8ca..416168a 100644
--- a/bar_option.go
+++ b/bar_option.go
@@ -2,6 +2,8 @@
 
 import "github.com/vbauerster/mpb/decor"
 
+// BarOption is a function option which changes the default behavior of a bar,
+// if passed to p.AddBar(int64, ...BarOption)
 type BarOption func(*state)
 
 func AppendDecorators(appenders ...decor.DecoratorFunc) BarOption {
diff --git a/options.go b/options.go
index 1736ae0..70a2691 100644
--- a/options.go
+++ b/options.go
@@ -8,6 +8,8 @@
 	"github.com/vbauerster/mpb/cwriter"
 )
 
+// ProgressOption is a function option which changes the default behavior of
+// progress pool, if passed to mpb.New(...ProgressOption)
 type ProgressOption func(*pConf)
 
 // WithWidth overrides default width 80