Here's what I have, You can get it at Costco for about 85.00 
I used a stool on wheels once. Was so proud. It was all brand new. Shiny red. I even put a coat of wax on the power coat before putting it in to service.
Rolled bike out in the driveway for a good wash and clean. This would be the driveway with the downhill slope. Got the bike all washed up. Set about finish chamois and then detail work. Dutifully working that pretty new stool sliding around the bike. I was no doubt just so proud.
Working on the rear of the bike. Wax on, wax off. Wax on, wax off. Mr Myagi would have been offering such jubilant praise. Then, suddenly, Don, his pride and his new stool and are scooting down the driveway. Zoooom. Tried to lay it down before getting to the street but, somehow, the stool didn't lay down. Driver came off, bonked head a wee bit. But stool continued on to the street. The score that day was F250 1, Stool 0. A sadness was felt all through the neighborhood.