Solid nylon martingale or buckle martingale collar. ID info can be laser engraved onto buckle. Martingales are limited-slip collars or no-slip collars. Martingales can have more than 1 color, with the 1st color being the back part of the collar and the 2nd color as the loop color. If you add a buckle, you can do a third color for the attachment part between the loop and buckle.