Flush trim bit with ball bearing guide. 1/4" diameter, 1/2" carbide height, 1/4" shank.
Amana Tool 47090 D: 1/4" B: 1/2" d: 1/4" L: 2-1/4" 1/4" diameter for closer inside corner cutting. Bearings not guaranteed due to size. Super clean cuts as well as Cost effective.