Abstract: A lock assembly includes an elongated generally U-shaped resilient shackle, a base block, and may also include a keyed auxiliary locking bar. A first shackle arm is slidably and rotatably secured to the base block so that the shackle can be moved between extended and depressed positions and pivoted between locked and unlocked positions. The base block includes a catch for retaining a second shackle arm in the locked position. To pivot the shackle so that the second shackle arm can be moved into or out of the catch, the second shackle arm must be flexed toward the first shackle arm. When the shackle is in the locked position, a locking mechanism holds the shackle in the extended position and requires the shackle to be depressed, while the second shackle arm is flexed, to pivot the shackle and move the second shackle arm out of the catch.