What's in the box:

BT 5.0 Transmitter and Receiver 2-in-1 BT 3.5mm Adapter Support 2 Devices Connecting in Transmitter Mode Wide Compatibility Black (Standard)

Features:
Receiver Mode
Change the traditional car stereo system or home audio system into BT-enabled ones. After paired, play music wirelessly from your BT-enabled smartphones, laptop, tablet, etc.
Transmitter Mode
Connected to the audio devices (such as MP3, MP4, TV, and PC, etc.) without BT function, changing them into BT-enabled ones. In transmitter mode, it can pair with two BT-enabled headphones or speakers simultaneously.
Strong Compatibility
This receiver and transmitter adapter can be widely used on your computer, laptop, home stereo system, headphone, smartphone, MP3 player, CD player, etc.
Low Power Consumption
Built-in 300mAh rechargeable battery ensures about 6 hours of working time, you can enjoy wireless music all day long. Easy connection, no driver needed, plug and play.
Convenient to Use
Switch between transmitter and receiver modes with the simple click of a switch. Mini and portable, easy to carry in your backpack or laptop bag and take it on-the-go.

Specification:
Product name: BT Adapter
Color: Black
BT Version: 5.0
Protocol Supported: HSP, A2DP, AVRCP
Transmission Distance: 10m / 33ft (open space)
Battery: Built-in 300mAh Rechargeable Li-polymer battery
Working Time: about 6 hours
Charging Time: about 2 hours
Input voltage: DC/5V
Input interface: 3.5mm audio cable
Item size:6.59*4.79*1.33cm / 2.59*1.89*0.52in(L * W * H)
Item weight: Approx.22.4g /0.79oz
Package size:9.1*7.2*3.2cm / 3.58*2.83*1.26in(L * W * H)
Package weight:61g /2.15oz

Packing list:
1 * BT Adapter
1 * 3.5mm Audio Cable
1 * Micro-USB Charging Cable
1 * User Manual