1/2 inch Piston Rod: Heavy-duty nitrocarburized rod for long service life All Weather Fluid: Contains special modifiers to reduce friction and ensure smooth rod reaction. Full Displaced Valving: Better valving range on both the compression and extension cycles of the unit for a smooth comfortable ride. Micro-Cellular Gas Design: Allows unit to be mounted horizontally. Sintered Iron Piston: Stronger than traditional metals, enhances durability for longer service life. Special Seal: 'Self-lubricating' fluid seal designed to retain gas without excessive wear or friction.