Customized Slide-On Dog ID Tags - Stainless Steel and Brass - Engraving Guaranteed for Life SIZE MEDIUM: 3/4 in- For 3/4&#34; wide collars. Opening will fit collars with thickness of 1/8&#34; or smaller. HIGH QUALITY: This ID plate is made from heavy duty stainless steel or brass. The engraving on the tag will last a lifetime. We guarantee it. LASER ENGRAVED JUST FOR YOU: Each tag is laser engraved using deep fiber laser etching. Your dog's most important information is easy to read and won't wear over time. LIFETIME GUARANTEE: We only the carry the best tags on the market, so we guarantee our ID tags for the lifetime of your dog. NOTE: Works on open ended collars only. This tag cannot be used with collars that have breakaway or quick release buckles, as the buckles are on both ends and are too wide for the tag to slide over.