easy way to get around the shop,great for sitting doing brake jobs and such on vehicles, it rolls pretty easy across uneven shop floors and the foam top is easily replaceable, just some hot melt glue holds the foam to the milkcrate so you can replace it easy. I guess you could bond the foam to plywood then screw the plywood to the top of the crate,this might help keeping your foot from breaking thru it if you were to step on it as a stepstool,altho thats a mighty treacherous thing to do as it wants to slide out from under you...the caster base is a dolly for a Rubbermaid Brute trashcan. this one has lasted about 25years or so..unbelieveable..this also is handy for painting things as a rotary dolly,just cover it with a trashbag,put your item to be painted on it,rotate as you paint..works great for me-FWIW

[Linked Image from kuhnbros.com]