Vello FreeWave Plus Wireless Remote Shutter Release - 2.4GHz (for Sony Alpha) Reduced Interference 2.4GHz Frequency | Range Up to 320' (100 m) | 16 Possible Channels Built-In Internal Antenna | Press Shutter Halfway to Focus | Four-Second Delay Multi-Exposure Function | Control Length of Exposure Remotely | Works Wired or Wirelessly Change Release Cable f/Different Cameras Whats In The Box: Wireless Transmitter, Wireless Receiver, 2Camera Release Cables, 4AAA Batteries, 1-Year Limited Warranty