This L size (9") Super Knuckle Arm has a ball head with 1/4”-20 female thread on one end that matches the universal mounting system of AbleNet switches. This arm is constructed by linking two S size arms with a 3" extension. The four ball heads of the arm allow users to adjust the mounted AAC switches to precise positions that suit their special needs. The extension arm has three 1/4"-20 and two 3/8"-16 female thread holes that allow for mounting devices using an additional Super Knuckle Arm. The Wheelchair Tube Clamp is equipped with a ball head that directly mounts into the Super Knuckle Arm. The Clamp can be tightly mounted onto wheelchair frame tubes and provides a very stable base. Given that there is no universal diameter for wheelchair tubes, three plastic spacers and a rubber strip are included allowing the clamp to fit 3/4" (19 mm), 7/8" (22.2 mm), 1" (25.4 mm), 1-1/8" (28.6 mm), 1-1/4" (32 mm) tubes. It is recommended to leave the tube clamp installed on the wheelchair so that it does not need to be remounted. The Super Knuckle Arm is easily released from the Wheelchair Tube Clamp by loosening the central knob of the arm. This set mounts an AbleNet switch or any equipment with 1/4"-20 male thread within a flexible 9" (22.8 cm) radius of a wheelchair tube.
This set can also be used to create "homemade Velcro mounting board with ball head" (see the tutorial video on this page). Using this technique, all kinds of lightweight devices, such as AAC switches and joysticks, can be mounted via Velcro tapes onto a board. The user is then free to adjust the angle of the mount with the Super Knuckle Arm.