6EA Heavy Duty Full Marine grade stainless steel, designed for corrosive and and salt water environments. Fit perfectly over standard BCD D rings for scuba accessory attachments 30mm OD x 1.8mm x 25mm ID ideal for camera housings, lights, lanyards, pointers, etc. Semi-polished finished also excellent for dog leashes, key rings or any area where you need to maintain a smooth surface finish that is free from rust or corrosion Made of quality 316L stainless steel, which is also superb for all boating quick release pins