A sleeve nut is a nut used instead of a turnbuckle, when high strength rods are required.

A new connection method, which used sleeve nuts to connect each main strand socket to its anchorage rod, was also used.

Fixings to newell posts to be combination of stud fixing on deck side and sleeve nut on mezzanine void side.

However, those clever chaps at LA Supertrux have designed the spacer to accommodate a sleeve nut that goes through the chassis and the spacer.

Which means that you either need a pair of extra long bolts with a tube to fit the hole in the lift spacer or preferably a length of stud to fit into the sleeve nuts and turn them effectively into long bolts.