AirTAC NPB Series Imperial Roundline Pneumatic Cylinders come in double acting, single acting, and double rod models. Select from double acting, single acting, and double rod models with the following bore size options: 5/16”, 7/16”, 9/16”, 3/4”, 7/8”, 1-1/16”, 1-1/4”, 1-1/2”, 1-3/4”, 2”, 2-1/2”.