Ifwe are very fortunate that you can buy our products,you will get a gift(adjustable frequency ultrasonic dog training whistle) ➤SimultaneousCharging The remote controller and receiver have built-in rechargeablelithium battery,and the general USB charging line can charge the remotecontroller and receiver at the same time. When fully charged, the receiver can work continuously for 3-6 days, and the remote control can work continuously for 6-12 days. ➤Adjustablenylon dog collar This dog collar with remote isuniversal for all dogs.With adjustable collar from 10-25 inches,the dogbarking collar is ideal for small,medium,and large size dogs from 8-250 lbs. ➤100%Water Resistant IP67 Level With this IPX7 rain-proof dog collar, you can also take your dog to the beach and seaside for swimming and playing games (note: the transmitter is not waterproof). ➤dog training whistle The highfrequency dog training whistle is a useful tool to control excessive barking. 1. Adjust thepitch and blow the whistling whistle to your dog. 2. You mayhave to wait until he falls asleep,then gently whistle. 3. Train yourdog with different sequences of dog whistle. How to usethis whistle for dog training? "Do notmove"(two short sounds) "Sitdown" (one long andone short) "over"(two long voices) Note:Pleaserefer to the instruction manual for the use of dog training collars.