High quality stainless steel construction Secure stainless steel wire gate closure Made of high quality, weather-resistant stainless steel, this ultra-handy accessory with its dual spring gates will hold, secure, and connect everything from keys to water bottles to gear. Smaller-sized S-Biners are excellent for connecting two zipper sliders on backpacks, duffels, and suitcases. We know that one size doesn't fit all, so we've designed six different sizes so you can choose the right size for the task at hand. We've found that the smaller sizes work great for hanging smaller items from a purse or backpack strap, attaching to individual keys, or hanging a plant from a ceiling hook. The larger sizes work great for bigger jobs like hanging a paint can from a ladder or a tool to your tool belt. The #2 holds up to 10 lbs., #3 holds up to 25 lbs., and #4 holds up to 75 lbs.