Going back to the 1950s, we see vintage trailers use spring loaded supports like these for table extensions, fold up shelves and writing desks. The spring loaded support comes in either 10" or 12" lengths. They are measured the entire length from rivet to rivet. It is well built from heavy gauge steel and offers a positive quick action when correctly installed. The support cannot collapse accidentally because the shelf or table is held in place by spring tension.
The weight limit is roughly 50 pounds, but load limits vary depending on where the support is mounted.
Sold Individually, does NOT come with mounting screws.