E821 Nylon Large/middle-sized Dog Collar Led Falshing Lights Pet 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-2.0cm x L-22 cm extends till 40 cm;Middle Size:W-2.5cm x L-32 cm extends till 50 cm;Large Size:W-2.5cm x L-48 cm extends till 60 cm;Xlarge SizeW-2.5cm x L-52cm extends till 60 cm