This caster wheel is manufactured to the highest industry standard. Designed to protect hardwood floors, tile, vinyl, etc. If one or more caster wheels on your office chair are broken, there is no reason to throw away the whole chair. All you need is this replacement caster wheels. The stem length is not critical as most chair base will accommodate a little longer or shorter stem. No special tool is necessary for the replacement job. Just pull out the old wheels and snap these new wheels back into place.