Sealey jacking beam yankee 3tonne with arm extenders flat roller supports sealey sjbex300 3tonne capacity and fully certified and approved to comply with vosa requirements features two stage mechanical safety lock and telescopic finger guards to prevent accidental injury supplied with two pairs of aluminium support blocks beam has spring loaded flat arms with roller bearings when unloaded these support the weight of the beam allowing the entire unit to run smoothly along the pit or r