Chair Casters Locking for Carpet Package of 5 fit most Alvin brand drafting chairs and office chairs. It does not fit the DC204. The chair casters are sold as a package of 5. The chair casters metal stem dimensions are approximately 7/16" diameter x 7/8" long. The wheel diameter is 2" for the locking chair casters. These chair casters are designed for Alvin drafting and office chairs. They may or may not fit other Mfg office and drafting chairs, Alvin chair casters.