Rock Hard Studs – solid 18K Gold. RockHard Collection is inspired by the love of rock climbing, mountains and the outdoors. A great symbol of Friendship, Trust and Safety . The piece measures about 10×7 mm (0.47×0.27 inches) Worn by many Friends! Climb on – on rock, ice, in life and work! These studs give back – as all my pieces do, – when you purchase from me you are giving back 1 % for the Planet! Enjoy good conscious shopping.