12pc 4" timberlok screw. No pre-drilling. Countersinking head style. Heat-treated for increased strength. Heavy-duty threads for holding power. Easily removable. The OMG timber-lok is engineered to drive right through pressure treated beams. For best results use a 1/2" high torque, low RPM power drill. 5/16" hex drive bit included. 10 count. 4"