... for MAKITA Planer such as N1900B, N1923B,KP0800X, etc. Spiral Cutterhead to replace the conventional straight planer knife:Carbide Insert ... small for easily chip ejection.3-1/4" (82mm) size Spiral Cutterhead for MAKITA Planer such as N1900B, N1923B,KP0800X, etc ... .4-3/8" size Spiral Cutterhead for MAKITA 1912B, etc. Spiral Cutterhead for MAKITA planer