The Twist 'n' Lock action handle guards against syphonic flooding and waste backflow. With one easy 90° turn of the handle, the lock is applied. Turning the handle back to the natural operating position opens the lock again.
This handle unit can be a direct replacement for the older version of the handle that was originally fitted to many Jabsco manual toilets.
Part ordered was out of stock however they moved earth and mountain to courier the part to me next day so 5 stars to this crew who cared business to business to get the part needed.