Review on Lion Locks Sliding Window and Door Locks (10 Pack), Adjustable Aluminum Security Screw Lock for 3/16-3/8” Track, Door Stopper Safety Lock, Easy Install, No-Drill Required, Requires 28-36mm Clearance for Screw Lock by Carlos Macy

Great product! Each lock works as needed, is well made and gives me peace of mind that my sash is secure. You can use it with or without the black rubber inside depending on the fit and even when I removed the rubber the lock still protected my window. I prefer these locks to the single screw ones, they are stronger than the ones I've tried. I tried opening the window with these locks and they held like a regular lock and didn't budge. Very happy with this product!