Auto-Locking #10 Brass Zipper

This style zipper is called an "auto-locking" zipper.  This type zipper/slider is commonly used in things like a pair of pants or applications where vibration/movement/gravity can affect the zipper.  They generally have a cam or spring loaded bar incorporated in the slider body mechanism.  In the down or "closed" position they either have a little brass pin that goes down between the zipper teeth, or the cam puts pressure against the zipper chain preventing the slider from opening inadvertently. 

This type slider is standard in our TAB/12 and TAB/18 stock bags.  We can put this type zipper in most bags we manufacture.
 

Non-Locking #10 Brass Zipper

This type of zipper is referred to as a "non-locking" zipper.  This just means that the slider body runs freely up and down the zipper chain without any interference. You would not use this type zipper/slider combination in a pair of pants because it would slide downward with movement eventually.  In bags or pouches it is an excellent choice because of the smooth nature of the design.  Also bags and pouches are not generally carried downwards and are not subject to constant vertical movement.  If this is a concern for a specialty application you can always have any stock TAB bag built with the above "auto-locking" zipper.