... +R+L three units, port size 1/4", manul drain type, model no. is AC2000 * Middle size, F+R+L three ... 1/4", auto drain type, model no. is AFC2000D * Middle size, Filter+regulator, port size 3/8", manul drain type, model no. is BFR3000 ... size 1/2", model no. is BL4000 AC/BC Series Filter/Regulator&Lubricator/FR.L Combination/Air Source Treatment Unit