The present invention pertains to extension arm apparatuses that are adapted to support user devices throughout a range of positions. A given apparatus may include one or more arms that position the user device remotely from a support position. An extension and retraction device such as a gas cylinder is received within each arm, and provides a force to support the user device as the arm is placed into a given position. A variable force clevis is connected to the extension/retraction device within the arm. The variable force clevis is connected to a pair of locations in the arm as well. As the arm moves, for instance up or down, the variable force clevis rotates within the arm and dynamically adjusts the force provided by the extension/retraction device. Thus, the arm may be positioned as desired, as such force adjustment stabilizes the arm.