A ratchet jack is a versatile mechanical tool used to lift heavy loads or hold them in place. It is designed with a ratchet mechanism that allows for incremental height adjustments and a locking mechanism to securely hold the load in place. The thread diameter is 1-1/4 in. with a length of 20 in. when closed and 28 in. when extended. It is a versatile tool that can lift, lower, level, and support heavy loads up to 20 tons with ease.