Aetertek At-211sw Small Dog Shock Collar Rechargeable Dog Collar for Dog & Cat, 10 Adjustable Level of Shock Correction AT-211D. use the most advanced design, turn the receiver on/off,bring the magneta circle on the back of transmitter) near to the magnet switch(the power button) on the receiver until the receiver vibrate.(if you have any other question,there is owner's manual on the package) Adjustable TPU strap length from 2" to 9", can be used for dog from 10-25 lbs,is only for small dogs. Multi-functional bark collar: Vibration, Beep, 0-10 adjustable level of Shock, LCD Display. sleep mode for long battery life Water-resistant dog trainer, pls DO NOT make your dog wear it when swim. 1 YEAR WARRANTY. the receiver size is too small,so the standby time just 1-2 days.