Trailer Aid Plus is the fast, safe and easy way to change a trailer tire on a tandem wheeled trailer. You pull the good tire up onto Trailer Aid Plus to raise the flat tire up 5. 5" for changing. Trailer Aid Plus has an additional 1" lift more than the original Trailer Aid and is perfect for RV trailers and horse trailers. It is great for horse trailers so you do not have to remove your horses in order to change a flat tire. The extra 1" lift is handy when performing routine maintenance on the trailer. Lifetime .