Large is 1" wide and adjusts to fit neck sizes 15.5" to 20.5" once the Fi unit is attached. Our Everyday Collars are made with polyester webbing, anodized aluminum hardware and USA-Made Duraflex acetal Buckles. This Fi-ready, one-of-a-kind collar features fun patterns to attach to your current Fi GPS unit. Our Fi-Ready Collars are lightweight, colorful, and durable. This collar fits Fi Series 3 and 3+ devices, and the Fi GPS unit is not included. Not intended for tie-out. This Fi-ready, one-of-a-kind collar features fun patterns to attach to your current Fi GPS unit. Our Fi-Ready Collars are lightweight, colorful, and durable. This collar fits Fi Series 3 and 3+ devices, and the Fi GPS unit is not included. Not intended for tie-out.