The size of the stainless steel ID tag measures approx. 40x 21mm/ 1. 57 x 0. 82 inch; The diameter of the collar ring is about 30 mm/1. 3inch. these pet tags are made of hardened Stainless steel, anti rust and corrosion resistance, scratch resistant and non fading, which are lightweight but reliable, will not have an effect on their activity, easy to carry and store.