I tried the Trailer Aid with my last bumper pull and when I needed it it wasn't tall enough; had to fidget for 30 minutes getting a 2x8 under it so it would work. Bought an Andersen Rapid Jack? and it worked better. After that trip the Trailer Aid came back, got threw out in the barn somewhere and is still there, somewhere, gathering dust in the dark (I suppose).
As Chuck mentioned you can also use your jack or I carry 2 8 ton bottle jacks as well. The Rapid Jack is just much simpler IMO.