After reading many bad reviews regarding the poor quality of master locks of this size, I happened on this Eagle Creek lock and cable.  I used the lock for a dual purpose.  I used the inside cable to lock in a gun safe and the outside loop and actual lock through the two zippers on the outside of the suitcase. (The suitcase also has a TSA lock thus giving double protection to frustrate any dishonest baggage handler).

If you don't have outside locks this item will work to secure your belongings on any zippered to close suitcase.  No worries about the TSA breaking it either.  TSA has opened and inspected my luggage twice and replaced it in the locked position

I am completely satisfied on how this item performed and the quality of the product.