There is a collar behind the chuck/bit with numbers 1-15...what do they mean and what is it used for? Also on the top of the drill above the trigger is a slide lever. Depending on which way you slide it, it displays 1 or 2. I can't even find the user's manual and I am just lost. This cordless drill is DW929 3/8" VSR 450-1500 rpm. If you can answer these two questions for me, then I don't need a User's manual. :-)))