These double-bitted keys are usually silver in colour (though brass ones crop up occasionally) and are normally about 8cm long. The key is similar to a Chubb key, but it has two blades, not just one. The blades are normally asymmetrical, and generally one blade has a bump on it (see photo above). The key might also have JMA FAC1G, FAC2G or FAC3G written on it.
