Both the Button Lock System and the Locking Clamp System give you the flexibility to use the same upright to go different heights. The Button Lock System uses a button lock that slides up and down the pipe in marked one foot increments and then locks into place.  This option is great if you know your Pipe and Drape set up will always be in adjusted in one foot increments. The Locking Clamp System is great because it allows you to adjust your Upright in-between one foot increments. For example you can set your Upright to eight and a half feet which really gives you a nice range of flexibility. Instructions on how to use the locking clamp ship with the order.