On the right we have a standard British safe key - single bit, male (pin type). The 3 main parts of a key are marked - the Bow or head which you would hold the key, the shaft or shank and the key bit. Depending upon the thickness of the door, the shaft between the bit and bow could be anything from 25mm (1") to 300mm (12")

Here we have a key made by British company Lowe & Fletcher. This is a double bitted female (pipe type). Notice the hole in the end of the key stem/shaft. This would fit onto a pin in the lock. Being double bitted means that the key may operate more levers and consequently could be more secure than  a single bitted key.

This is the Kromer double bitted key used on high security safes for many years. Note the oval shaped key head (bow). This key is quite long, so the door would probably be 3" or 4" thick. On thicker safe doors, the key shown below will often be used instead.

The Kromer lock that this key would fit would be the same quality as the one above, but the safe door would be much thicker  - usually because a larger amount of cash is held in the safe. As you can see, the key can be broken and the loose bit can easily fit in a purse or pocket. Often, key manufacturers will supply the key bits with a small wallet to keep the key safe from damage when not in use.

Tann plunger stem and loose key bit. Note the hooks on end and edge of the key stem.

Rosengrens RKL (re-keyable lock) stem and key bit.

Chubb stem and 'slip' bit - so called because the bit slips into a slot cut into the stem

Rosengrens ABN key bit and stem. This fits another type of re-keyable lock

Cawi double bitted key. This is a female or pipe key. Available in 6 lengths.

A higher security version of the Cawi range - double bitted with up to 14 levers.