One of the instructors out of a training company called Oregon Trail Defense LLC has come up with a modification for the Safariland ALS series of holsters. It’s called the “Nub Mod”, because essentially that is what it is, a small plastic piece that replaces the stock retention button on the existing holsters, in order to allow for a quicker and more natural flow of withdraw while keeping the advantages of handgun retention. It goes for 32 dollars, and they also have them in aluminum. This is what they have to say about it-

Faster:

The reversed angle matches up with the pad of your thumb sooner than the factory button. You will find the gun in your hand just by grabbing it.  Weak side draw becomes much faster as well.

More Reliable:

The wider release button means you have even less potential to miss the activation, especially on thigh rigs or mounting systems that push the holster away from your body.

If you have ever found yourself  pulling up on the gun before hitting the release you’ve noticed that gun is difficult to almost impossible to get out. The additional leverage of the Nub Mod fixes this stress induced or poor training problem if it ever arises due to the increased surface area for the thumb to engage.

Stronger:

Many find the button too small and glue or plastic weld onto the button to make it larger. This has the potential to make the typical homemade button get pushed over into the body of the holster rendering it inoperable.

The machined aluminum piece is indexed in part by the outside edge of the factory button. It will not come over the edge of the holster. It is bead blasted then hard anodized.

The Nub Mod as packaged. 

They included a description of some of the holsters that it won’t work with as well-

The Nub Mod will not work with the Safariland ALS Guard.  It will work with the ALS Hood only.
The Nub Nod will not work with the 1911 ALS holsters, the portion of the holster that protects the safety inhibits the Nub Mod install.

The Nub Mod will not work with the older style ALS holsters that have the ‘step’ into the holster body without a fair amount of work. See images at base of page.
It will not work with the SLS without some modification to the holster and/or nub.  If you were to modify your holster slightly to increase the standoff space it would still be a tight fit, tight enough that your draw would be signicantly slowed down if putting down the SLS hood then activating the Nub Mod/ALS. Leaving the SLS hood down would result in the same benefits as the ALS only.  Do so at your own risk.  I do not recommend it!

A dedicated SLS version is in the works and should be available October 2015.

I really like this little tidbit here-

Apply LocTite or your favorite color fingernail polish to the threads and insert screw in the large tapered hole. If you try to screw from the gun side please sell all your guns.