The Tile and Cube Tracker Fastener comes in two sizes Small for 1.35-inch tiles and cubes, and large fits the 1.65 pro tiles and cubes. Both fit any pet collar or strap up to 1.5 inches wide and come with solid loops due to the material's rubber-like flexibility. . The fastener is part of our flex fastener line and is made from a soft flexible TPU which makes inserting and removing the tracker for battery replacement easy! Available in White, Black, or Gray