Centerline systems offer features not found on other comparable systems. The computer designed shape of the aluminum tubes on our aluminum system makes Centerline the stiffest (by up to 30%) aluminum system on the market while maintaining the advantage of lightweight portable aluminum. Premium features include: lifetime warranty net tensioning winch and standards, floor friendly adjustable feet, dual pin and lock knob spring assisted height adjustment, bold engraved height indicators. 34 lb. post weight. Systems install in any 3" floor sockets or 3 1/2" and 4" sockets with adapters provided free on request. Includes standards and winch only. Shipped freight. Made in the USA.