Misc. What is this electronic part?

[exctmt]

I purchased a Piper Cub J3 1800mm kit form RedwingRC.
This part came with the electronics. I received the engine, four servos, ESC and this part.
I reached out to four times to RedwingRC and they have never replied to emails or voicemails..
By the way they had no problem selling me the original plane and order.
Maybe they went out of business?
Can someone tell me if I need this. I have the receiver bound and the motor runs, and the servos work, without it.
Thanks

 

[RandyDSok]

I believe it's simply a BEC ... a battery elimination circuit. If correct ( without a label or model number hard to say with certainty ) ... there are two reasons you'll see these.... High amperage ESC's often do not come with a built in BEC so some method it needed if the flyer isn't supplying power using batteries. The other standard use case is the BEC's often built into the ESC's will have voltage or amperage limits that require more on some builds... ie may be limited to only 5v or perhaps just a few amps of current. In those cases, using a seperate BEC can help resolve the lacking of the built in BEC may have.

 

[exctmt]

I guess if I knew how to hook it up, I would. But like I said I get no response from RedwingRC.
Like everything else, it came with no information.
Maybe I will play with it at a later date.
Thanks.