Over-The-Air (OTA) programming device fits in your pocket
OTA Programmer is a module which adopted the BT communication technology for transferring data between an ESC and a smart device (Android phone, tablet, and etc). It makes the wireless communication between ESC and smart device possible; the user can easily program and upgrade ESC and monitor data transferring via this unit.
Features / Why you need this?
HOBBYWING over-the-air firmware update. 
Programming through a smartphone, smart devices  
Access to HW Support*  User Manual, Profile manager, etc
Fail-safe feature ( Disable a throttle control when OTA programming is enabled) 
Works with the following products of HOBBYWING.
Some of XERUN series & EZRUN series of car ESCs.
Some of PLATINUM series of aircraft ESCs.
Some of SEAKING series of boat ESCs.
For details, please refer to ESC manual to ensure if the ESC can work with OTA Programmer.
Specification:
Working Voltage: 5V-12.6V.
Supported BT Version : ≥ 4.0 • Effective Range: 0-3m (Open Field).
Size: 30.0x25.5x8.5mm (LxWxH).
Weight: 10.2g.