I use a standard L&H harp cart for my concert grand Camac. I use a Staples $52 fold-up cart for my Webster Cecelia. The Staples cart holds 250 lbs., but I wouldn’t put my big harp on it because it isn’t sturdy enough. They both work great for me. I wouldn’t want to do stairs with either one though. I do get them down a threshhold at the door, and a berm in the garage, but not a lot of steps. I always wondered about those 3-wheeled things. They are intriguing to me.