Pre-made Ipe Plugs simplify starter board installation when using Eb-Ty fasteners. These 3/8" dia by 7/16" long flat grain plugs are gently tapered, so they slip right into countersunk hole. The wood plug diameter is 0.353" and tapers up to 0.395". Glue them in, then pare them down with a nice sharp chisel. Made in USA.