BLUE BOAR 1-3/8" (35mm) MEGA Tungsten Carbide 2-1/4" deep hole saw TCT Hole cutters cut holes up to 10x faster and last up to 15x longer than bi-metal hole saws Use any standard 5/8" - 18 thread 2 pin hole saw arbor and any standard 3-3/4" or longer pilot bit 2-1/4" cutting depth best when USED with 18v Cordless Drill set on SCREW SETTING ****NOT for use with 1/2" stud drills such as Milwaukee Hole Hawg which will rip the teeth off **** Unique tungsten carbide tooth design wide kerf allows fast plug removal