Abstract: A lock configured to lock retractable devices such as retractable landing gear for aircraft in a retracted position. The lock comprises a pivotally mounted hook member with a hook portion arranged to maintain a capture pin attached for example to retractable landing gear in a predetermined position when locked. A pivotally mounted first stage latch assembly is provided having a portion arranged to engage with a corresponding portion on the pivotally mounted hook member. A pivotally mounted second stage latch assembly is also provided having a portion arranged to engage a corresponding portion of the first stage latch assembly to maintain the first stage latch assembly and hook member in the predetermined locked position.