To help in determining what lock mechanism you are asking about

The Pictures below are to help identify keys some times the keys maybe a different size for example: Pin tumbler key for some padlocks are under 2 inch length 

 

Here are examples of places to look on a lock to help identify the lock

In the red boxes Left to Right Picture 1 Manufacturers name on front, Picture 2 other identifying marks example:(name,holes,cross,codes), Picture 3 Manufacturers name on latch if not on front or hard to read on front  

 Picture 1 Picture 2Picture 3

Example of code found on cabinet locks is in red box