Independent Quality-Assurance Tested to Highest Safety Standard: Voluntary compliance to ULs inversion table safety standard makes Teeter Hang Ups the only inversion brand with certified quality. Ergonomic Flex Technology: Our patented design moves with you, accommodating stretches for greater range of motion. Movement while inverted encourages realignment and relaxes muscles. Pre-set Rotation Control: The adjustable or removable tether strap allows you to easily pre-determine your maximum angle of inversion. Easy Assembly: The EP-550 arrives 90% pre-assembled. The engineering group evaluation reported 13 minutes of assembly time for the Teeter, in contrast to the other brands which required an average of 71 minutes.