SEE HERE FOR PREVIOUS TRITIUM KEYFOB REVIEW
Quick update on my merkava II tritium glowring:
Unfortunately with time my merkava II tritium glowring, has finally cracked and broken. The tritium vial inside still seems to be fine, only the other casing is broken.
I wouldn't recommend putting this tritium marker on a keyring, its better suited for applications where it would get less abuse. The main benefit I see in the merkava II, is that it is the smallest and thinnest tritium marker, that contains a 23x3mm sized tritium.
I have put in a order for some empty tritium holders to install the spare tritium myself. I have found the empty holders from LESLIEx317537 have held up well so far.