We use ultra-strong Weinerlock brand buckles made by the National Molding company. The D-rings are heavy-gauge metal with welded ends for added safety. Our collars are made from strong, water-resistant polyester material that is permanently infused with the rich design colors. These colors will not wash out or scratch off. All photos are taken using our large size collar. Please visit our Amazon store by clicking on 'PatriaPet' at the top pf this column. Large size is 1 inch in width and adjusts from 16-26 inches in length. Proper fit should allow for two stacked fingers between dog's neck and collar.