This is a straight forward item that assists in training safety and identification. To install ones just breaks their gun down and replaces their real barrel with this one. No tools or wacky techniques are required further than what your weapon already required. Once in, there is no way for bullets to be chambered so the weapon is completely safe even with live magazines inserted. When in normal slide forward mode, the training barrel can easily be seen with all of its bright yellow glory in the ejection port area and muzzle end. Alternatively, when the slide is back, more of the barrel is visible while the ejection port yellow can only be seen from the rear.
Personally I like to use the training barrel when I am doing dry fire exercises off and on throughout a day. I can pick up the weapon and immediately manipulate it in confidence since the yellow is easily visible. Otherwise one has to blow a little time double checking to make sure no rounds are in the chamber and no loaded magazines are inserted before "playing" with their gun. The usefulness applies in groups as well for displaying the safe status to others when on the range or during training.
The only downside is one cannot practice racking their pistol as if it had a minor malfunction in a real situation. The normal functionality with ammunition in the magazine would be for the weapon to automatically release the slide after a rack since ammo is still left in the magazine. With the training barrel, the slide will release after a rack if ammo is in the magazine, but since the bullet has no where to go, it will just be smashed between the slide and hole-less training barrel. Other than that, this product is simple while accomplishing its design goal well. It is a cheap way to turn the pistol you already have into a training weapon rather than having to buy a more expensive and totally separate dummy training pistol. As you may have guessed this product is not one size fits all, but luckily it is currently available in many pistol models used by MIL / LE.