This 100 gram loose weights are crafted of high-quality 316L ASTM F-138 Implant Grade Stainless Steel. The dimensions of the weight are 20mmx50mm. At the top of the weight, is a 5mm drilled hole. The hole can be utilized by sliding the weight onto a piece of jewelry, such as a captive ring. You can also use the S hook that comes with the weight to attach it to jewelry, ball weights or nipple clamps.