Product color: blue, pink, green, red Product size: 2.5cm wide S size: 32-43cm M size: 39-51cm L size: 44-64cm Battery model: 501225 rechargeable lithium electronic battery, capacity 110mAh (milliampere) 0.407mAh (capacity) voltage 3.7V; Work on at 5 hours for fast flashing and slow flashing can be working 9 hours; charging time about 2 hours. Efficacy: Avoid the possibility of being undetected when going out at night, attracting the attention of passers-by and vehicles, and can better go out for a walk or even run. The D-shaped buckle can be linked to the traction rope for daily outing use, when the light is turned off It can be worn and used during the day, it is convenient, durable and light in weight, so it won't tire your pet's neck. Waterproof feature of pet collar can be work to use in the day, what ever the rainy day or swimming both can glowing. Notice: Please allow 1-2cm measuring deviation due to manual measuremant. 1 inch = 2.5400000000102cm Due to the difference between different monitors,the pictures may not reflect the actual color of the item,thank you~