A mechanism for retracting and extending a length of flexible material including a gear mechanism having a toothed gear, a coil spring, and a stop mechanism. The stop mechanism includes a trigger button, at least one barb and latch combination and a gear tooth engaging member. Pushing the button a first time causes the barb to lock in the latch and causes the tooth engaging member to engage gear teeth, preventing movement of the gear and preventing extension or retraction of the flexible material. Pressing the button again releases the barb from the latch and disengages the tooth engaging member from the gear, enabling the gear to rotate to extend or wind up the flexible material.
