Abstract: An extensible tether apparatus comprising a flexible cord attached to a ring at a first, fixed end, a first loop formed by passing a second, free end of the cord through the ring, a second loop formed by passing the free end of the cord through the ring, and a third loop formed by passing the free end of the cord through a channel defined by the first and second loops. The length of cord adjacent the free end and the size of the third loop are adjusted by slidably extending or retracting the cord through the channel formed by the first and second loops. When tension is applied to the cord at the free end and/or the third loop, the first and second loops frictionally engage the portion of the cord passing through the channel in the first and second loops and prevent the cord from slipping from the adjusted position.