Locks automatically when you open leg or raise shelf, cannot be loosened until the release catch is pressed. Excellent for card tables, strong enough for ping-pong tables.
For extra large tables with heavy legs (like those made from 2 x 4’s) order the larger heavy duty model.

Use standard model for legs no wider than 1 5/8"
Use Heavy Duty model for legs no wider than 1-11/16"