bed caster, 1. nylon material, 2. dia 50mm, 3. with and wthout brake, 4. with M8*50mm or 5/16"*50mm thread. bed caster ,A. black, white, are available.B. loading 30--40KGS per piece;C. Has SGS certificate;D. used for movable furniture.E. packing:4pcs/polybag,200pcs/ctn. JH50-HA bed caster