Shift Lock, 15 pounds, released by HI-SP Storm. I purchased a new 15-pound 4-ounce ball and had it drilled, but I made a mistake with the measurements and drilled it with a short span, so I haven't bowled with it even once. I was thinking of redrilling it and using it someday, but I don't think I'll have the opportunity, so I'm putting it up for sale. Balance hole included. I'll also include a SeeSaw cloth to put the ball in and quickly wipe off any dirt (color cannot be specified).