The lock extensions provide an extra inch of height of clearance underneath. The extenders rest in the cut out of the post. You must have a lock height extension on all four posts when in use. To use the extensions you must raise slightly above the desired lock position, insert the extensions in each post, and then lower the lift onto the extensions. These extensions do not work on the top lock of any SS series Advantage Lift. (Set of 4)
These are an ideal solution when you need an additional inch underneath, but do not have 5" of ceiling height available to make the next lock.