1-2" black office chair caster wheel hadlement:zinc plated finish capacity:20kgs,25kgs function:suitable to the plant mover,light duty move,office chair etc. Item numberwheel diameter(mm)plate finishoverall height(mm)screw length(mm)screw diameter(mm)BT4040zinc plated finish/chrome5315/20/308/10/12,3/8",1/2"BT5050zinc plated finish/chrome6015/20/308/10/12,3/8",1/2"