E821 Nylon Big/Small/Middle-sized Dog Collar Led Falshing Lights Dog Collar LED pet collar;Material: nylon webbing Flashing modes: slow,faster or keep on Battery: 2 batteries that can last up to 100 hours Small Size: W-2.5cm x L-35 cm extends till 40 cm;Middle Size:W-2.5cm x L-40 cm extends till 50 cm;Large Size:W-2.5cm x L-50 cm extends till 60 cm