Gundlach No. GS-300-14 1/4" Colorant Replacement Brush
The Colorant Groutstick is also supplied with three brushes for use on 1/4", 3/8" and 5/8" wide grout joints. A reducer is also supplied to hold the brush bristles closer together. This allows colorant to be applied to joints narrower (down to 1/16") than the nominal brush width.