Make sure your things won't tilt and tip over inside your trailer with Stick-On Levels, model 28-0132, from Prime Products. It will let you know if you have attached it to high or low to your vehicle and needs to be adjusted. The RV levels come two on a card, with an adhesive backing that allows you to peel and stick, no tools required. It is available in multiple colors, including white, and is shaped like a trailer with the measuring liquid in the center. A bubble will travel to one side if it is uneven and stop in the middle when it is perfect.