Pressd steel swivel castor with a top plate fixing fitted with a 65 shore A black elastic electrically conductive rubber wheel on a black nylon centre with ball bearings and a total lock brake. Wheel diameter 150mm, tread width 40mm, overall height 190mm, top plate 105mm x 80mm, hole centres 80mm x 60mm Load capacity 300kg.Conductivity range is 10^3 ohm to 10^4 ohm