Sizing Guide [https://petbright.co.uk/pages/lux-led-collar-size-chart] Combining unbeatable low light visibility with premium design our Lux range takes all of the fantastic functionality of our original LED light up collar and takes it a step further. With it's high quality design, padded inner layer and LED stud lights running its length, it not only looks great but performs to keep your pup looking great by day and shining bright by night. Key features: * USB rechargeable for over 10 hours runtime; * Super-bright LED stud lights visible from up to 350 yards; * 3 light modes: Solid, fast flash and slow flash; * Weatherproof; * Padded faux leather inner layer; * Made from durable high tension nylon; * Adjustable Zinc alloy buckle; * Double row of reflective stitching.