Caution: color: we ship according to the color of the first picture, in the package: If the quantity is not stated in the description, we will ship the item according to the quantity and model in the title.If the title does not have a quantity, it is 1pcs. 3.5Mm jack wireless bluetooth receiver adapter black-1 the product is shipped based on the color or size of the main image of the product page. Colour:black-1 transform any audio system in your household or car to a bluetooth capable device instantly. Interface: 3.5Mm wireless type: bluetooth pairing timeout shutdown: shutdown after 5 minutes of pairing status this kind of bluetooth noise-reducing answering device, supports any key to answer calls, connects effectively with the smartphone, automatically matches the connection program, and maintains the connection state when charging. - Sound insulation, high definition call: identify sound frequency through intelligent control chip, and generate reverse signal to filter out external noises noise and wind within the range of non-human voice frequency. High definition calls in any noisy environment. System status: power off: mfb long press for 3 seconds volume up: short press vol+ volume reduction: press vol- switching languages: double-click and hold mfb in the pairing state red and blue lights flashing music control: play pause: press mfb last song: vol- press for 2 seconds next song: vol+ 2 seconds telephone control: answer the phone: press mfb when calling reject the call: the duration of the call is mfb unsigned redial: double-click the mfb key, then press mfb to cancel the dialing led display: power-on pairing: red and blue lights flashing alternately connection status: blue light flashes slowly 5 seconds 1 time low voltage: red light flashing 0.5 Sec 1 working current: status parameter 4.00V 3.40V rated operating voltage 4.00V 3.40V matching state current 4.33 Ma-20.56 Ma 4.47 Ma-22.03 Ma standby current bluetooth connected 0.43 Ma-8.31 Ma 0.41 Ma-8.74 Ma play music current 19.04 Ma-23.21 Ma 22.85 Ma-23.74 Ma the call current is 23.82 Ma-24.05 Ma 25.19 Ma-25.78 Ma charging current 100.0Ma. 100.0Ma power off current 1.4Ua 1.1Ua