All stackhouse four wheel liners use a heavy duty, 20 gauge steel body with an attractive blue enamel finish. The liner body has been designed so that its wedge shape ensures a constant flow of chalk to the bottom of the linear. Our liner gut, which is driven by the liner wheels, has an auger at each end that forces the chalk into a six bar expulsion wheel which ensures a constant flow of chalk. The liner ride on rubber diamond tread wheels that use a steel hub with oilite bearings for minimum rolling resistance. The liners offer both a 2' and 4' line for baseball, football, and soccer fields. These features, combined with the 5 models we offer, allow you to pick the best liner for your needs and budget. Line King 150 This heavy duty, 50 lb. capacity liner is ideal for lining mulriple baseball fields. 10' pneumatic wheels give a smooth rolling ride for easy field lining. Note The 'chalk', Calcium Carbonate, needed for this item can be purchased from your local farm supply o