Dog Barking Control Devices, Ultrasonic Dog Barking Deterrent Devices w 3 Frequencies Immune Proof, USB Rechargeable Handheld Dog Training Tool Barking Behavior Hat Sun Protection professional sharpening system for all professional sharpening system for all your cutting tools Ultimate Versatility The 4in1 Knife Sharpener combines the functions of a knife sharpener The bath sponge quickly lathers in water 3 different frequency wave to avoid dogs getting used to simple frequency this ultrasonic dog bark deterrent can emit ultrasonic sounds with 3 different sound waves stable frequency undulating frequency and irregular frequency sound waves you can choose the different waves to void dogs getting used to simple frequency and it can make it reduce the training effect on the simple waves for a long time Recharge dog barking control device with low power light Indicator this sonic bark deterrent usb rechargeable 300mah battery full charge in 1 to 2 hours for about 12 days of regular use saves you the endless hassle and invest in batteries when low power push the function button the indicator will be red