Elite Tactical Systems, aka ETS, makes translucent polymer magazines. Most notable for their Glock magazines. They also make a line of AR15 magazines with molded in couplers. Well recently they have collaborated with Advanced Combat Solutions to offer a blue AR15 magazine follower with a tritium insert at the back. It is used in ETS's transparent AR15 magazines.
Tritium is a low grade radioactive material. It is most commonly used in night sights for handguns. Unlike glow in the dark (GITD) material, Tritium does not require any light to charge up. It has a low glow that can been seen in the dark.
This could be used to see how many rounds are in the mag if you are looking for it in the dark. However once the follower has retreated into the magazine well you know that mag is almost out. However since tritium has such a low level of lumiecense, I am not sure how helpful this will be.
I could see this helping if you use an AR15 for home defense and you need to find a spare magazine in the dark. But once you use a light or turn the lights on, the tritium becomes useless.
I am concerned that repeated use of the magazine and this follower, carbon will seep into the magazine body just from shooting it. This could obscure and reduce the visability of the Tritium insert.
No word yet if ETS and ACS will take this design and apply it to ETS' Glock magazines. Rather than be used as low light round counter, I think it would be better suited as simply an identification and location aid. I keep my FNX45 Tactical by my beside and I like the tritium night sights so I can see where it is in the dark. The same would apply if ETS offered these followers for their Glock mags. You could have your night stand gun and mag with tritium and easly see them and locate them in the dark.
Right now they are available on ETS website for $14.99. Hopefully they wil be sold through Gun Mag Warehouse.
In the meantime, you can stock up on ETS AR mags. They are on sale for $14.99. Click here to check them out.