These are NOT reusable once LOCKED. 1 time use ONLY These are TINY. Please verify that you understand the size prior to ordering. Link Lock™… It’s the fastest, easiest, most secure way to join jewelry without soldering. Make a secure connection in just three (3) easy steps. You can perform this valuable service while your customer waits. Simply grasp the Link Lock™ with a pair of pliers, close the link with a second pair of pliers, then turn the locking flap into position. It’s that easy. Dimensions when closedID: 2mm X 3.50mm OD:4.50mm X 5.0mm Thinner section is 20 gauge Thicker is 14gauge 0.056 DWT (0.087 grams)