Isotope S323 - Stainless Steel Lantern Design Housing for 3 mm x 23 mm Glass Tritium Vial (Not Included) - Everyday Carry Tritium Keychain Accessory - Cool Keychains Accessories

Fit and finish are fantastic. Holds a 3x22.5mm vial perfectly. Mine also shipped with two rings and three small rubber plugs to ensure the vial does not float freely back and forth within the fob. I only needed to use one of the rubber plugs (and one ring, obviously), but I am a big fan of vendors who provide extra components.I have dropped my keys and the vial has been fine. I also don't see how the fob would flex very easily, but granted, it's not a solid cylinder wall due to the cutouts, so I suppose with force it would flex. I just don't subject my keys to that much abuse. ;)In general, I am extremely satisfied with every aspect of this product except its price. $19.99 seems to be the point beyond which this seems fairly pricey, especially when one considers you also need to drop $20 on a vial. Oh well, you can pay less for lesser quality. I decided not to cheap out.BTW, with regards to the vials, green is definitely the brightest, but don't believe claims of "daylight bright". Not given the size of the vial. I have purchased green vials from multiple sources and their brightness is all about the same, which is a pleasant glow in darker lighting conditions.

This tiny little keyfob is well made and very durable. It does an excellent job protecting the vial held inside it. I'm pretty rough with my keys, tossing them on tables, dropping them, swinging them around in my hand--even though all that, this fob protects the vial inside just fine. And it looks nice to boot.This fob takes a 3mm x 22.5mm vial, and the fit is perfect. Note that the fob comes with two rubber pads plus a keyring. The two rubber pads do not mean you get one extra! Use both by placing one in the bottom of the fob before you insert your vial, then use either the vial itself or something like a coffee stirring rod to push the rubber piece down. Insert your fob, then squeeze in the second rubber pad and push it down. There will be enough clearance between the keyring hole and the top of the rubber pad for the keyring to go in on top of the pad, keeping everything in place unless you remove the keyring.If you need to remove anything, you'll need to remove the ring, then use a very fine tool to push up from the bottom on the bottom rubber pad. This will force all the bits up and out.12/30/2015 Edit: 6 months and still good as new. Durable little thing.

Out of a few options available on Amazon, this one seems best suited for a necklace. If you need something tougher, opt for titanium.Pros: This fob is very compact compared to some bulky titanium options. It has as many openings for the tritium vial to shine through as possible without compromising strength (too much). It has a lovely polished finish. Your vial just barely fits in the tube and will not bang around, especially if you can fit the tiny rubber plugs at both ends.Cons: Due to its compact design and number of cutouts you can bend this fob with your fingers. Don't try that after inserting the tritium vial! This fob probably won't protect the vial from cracking if carried on a key chain in your pocket.

This is the 2nd one I purchased. I enjoyed the first one immensely, but unfortunately I lost it. Combined with the tritium Isotope, it makes a great addition to your keychain and helps locating your keys in low light environments. The tritium glows for a long time (years) and the holder is made of sturdy steel to protect the glass Isotope insert (which you much purchase separately). High recommendation for material quality, value for the money and fast shipping time.

Looks cool and has a great finish, but this thing is NOT strong or sturdy--it bends very easily, and my vial broke within a few weeks. I kept mine on a keychain in my pocket and in a bag, but nothing extreme or abusive. It bends VERY easily with very little pressure, even from your hands. Unfortunately it is of poor quality, and when you pay what they're asking for for such a tiny piece, you expect it not to break the vial it claims to protect. Really disappointed. Avoid if you want to actually take this anywhere.