Hi, remove one of the screws and take it to your favorite hardware store. Buy one screw, of the exact same size, made out of stainless steel, for every light you have. Then you need one stainless steel flat washer for each screw. And finally "O" rings that fit onto the screws. Install with the flat washers on the screws first, then the "O" rings, so the "O" rings are against the plastic lense. The washer prevents the "O" rings from slipping over the screw head. Do not over tighten and crack the lense.