The Stander EZ Adjust Bed Rail is the only bed rail that adjusts in length after installation.  Works well as a side rail to keep you from falling out of bed, as well as a support bar for getting in and out of bed.  It adjusts from 20" to 30" with the push of a button.  Can be installed on either side of the bed in between the mattress and box spring.  Works well on any twin to king size (non Adjustable) bed with Mattresses of 10" to 14" of thickness.