Material design – icon size in navigation drawer

I was wondering, in material design, what should be the icon size for navigation drawer.

I had gone through https://www.google.com/design/spec/patterns/navigation-drawer.html# , but they didn't mentioned on icon size.

Some had mentioned the size should be 24dp - http://stackoverflow.com/questions/28118325/what-sizes-should-an-image-in-an-navigation-drawer-be, but doesn't provide reference source to support his answer.

I had created both 32dp & 24dp version (Please to left side icon. I didn't did any change on right side icon)

32dp

24dp

I was wondering, which is the correct spec?