Great chamber safety option for many weapons - UTG Pro Universal Firearm Chamber Safety Flag, Set of 6

First, "universal" only goes so far with this type of device, so think about what your weapon needs to use the flag in the first place. For my needs - an AR-platform rifle I set up as a dedicated 22LR trainer, this was great. I trimmed the length for easy install & removal, and you can trim as much as you need to fit a variety of weapons. However, the thick handle end won't work well with a number of pistols for example, so look for some of the other flag options with flatter handles. Overall, this fit what I needed it to fit, is durable, and highly visible in a range setting.