What casters should a drafting stool have for hard floors versus carpet?

On carpet, standard black twin-wheel casters roll easily through the pile; on hard floors — hardwood, tile, or polished concrete — use soft polyurethane or rubber-tread casters to prevent scratching and provide grip. Most commercial drafting chairs ship with carpet casters by default — specify hard-floor casters at the time of ordering. FindOfficeFurniture.com can specify the correct caster for your floor type — call 888-719-4960.