Worthington 308970 20-Pound Outdoor Power Equipment Aluminum Horizontal Propane Cylinder, 4.7 Gallons, Green Collar Horizontal use only, vapor service only and vertical fill. Collar painted green for product differentiation Liquid prevention device (LPD) that covers end the end of vapor tube Includes fast fill valve with OPD Left-hand male and female safety couplers Standard fittings include: Safety relief, float gauge, fixed liquid level, vapor service valve