Hanayama Huzzle L2 Key2

The KEY 2 Metal Brain teaser puzzle consistS of two very similar looking old fashioned metal padlock keys. Your objective is to separate the two keys and then re-join. A small, compact, hand-sized, tricky puzzle. NO FORCE needed. This puzzle is moderately challenging. Hanayama rates this as a level 2 on a scale of 1 to 6.