If you are experiencing unexpected issues such as short work range, audio cutting in and out, not pairing, etc. you may need to clear the paired history of the HT4186 headphones and transmitter.
Clear the paired history of the transmitter:
After power on, press and hold BOTH A and B till you see solid pink lights from both A and B Blue tooth symbol. Then unplug the Micro-usb from the transmitter.
Clear the paired history of the headphones:
After turning on, press and hold both “+” and “-” for 10 seconds until the RED and BLUE LEDs are BOTH on for 2 seconds (looks PINK) - now all the paired history of the headphones is cleared. It then enters pairing mode automatically with the LED flashing alternately RED and BLUE.
Pairing the transmitter and headphone:
Plug the micro-usb back into the transmitter, then pressed the A button till it flashes red and blue. put the headphone (which is flashing red and blue) next to the transmitter, wait for the LED one the headphone turns solid blue and the Bluetooth symbol on the transmitter turns solid blue.