An intuitive mechanical combination lock A199 with industry standard panel piercing allowing retro - fitting to existing installations. The lock allows the end user to set and change their own 4-digit entry code and has a simple key override which also allows a manager to discover the code in use. A unique switch on the rear of the lock allows it to be set for left or right hand operation reducing stock and cost. This makes it ideal for various applications including Lockers and Metal Office Furniture.