Forstner Drill Bit Set-16pc Hardened and Tempered, High Carbon Steel Construction. Precision Machined Cutting Tips. Maximum 5,000 RPM. 3/8" Reduced Shanks Fit Nearly All Drill. Bit is Guided by Own Edge to Bore Straight, Smoonth Holes in Wood. Designed to Make Professional, Flat-Bottom Holes, Pocket Holes, and Clean-Thru Holes Revomable Plastic Covers Protect Cutting Edges. Complete with Blow-mold Case