I'm using this. Works fine for my 32ft TT. Thought it was broke until i figured out you have to turn on the headlights for the prewired box on the camper to get power.

https://www.amazon.com/gp/product/B07GVHJQYK/ref=ppx\_yo\_dt\_b\_asin\_title\_o03\_s00?ie=UTF8&psc=1