Streamlight 88130 Jack-Cap Accessory and Replacement for use ProTac Rail Mount Pro Models, 88126, 88127, 88128, 88129 only.

Seems to work fine with the Protac HL-X ten tap takes a holosun or stream light crane plug

I'm using this on an HL-X 88066 and it works as described. It's very beefy, but does not expand out any further than the light's bezel. If you're looking for something streamlined and lightweight, this is not for you. The biggest takeaway is the fact that this cap will accept a standard CRANE plug as found on LAMs, so you can save a few bucks by finding surplus plugs vs using Streamlight's.

It feels very well built. The light no longer cuts out when it's on and being fired. It was designed to work with streamlight version of the crane plug.I tried a knock of Unity hot button that stays reasonably secured, had to reinforce it with butyl tape. As in put some around the crane plug near the prongs and force it in. It takes a good bit of force to get it out once done this way but it's definitely secure. It just barely goes in far enough to work though. The knock off does work.Bought an actual Unity hot button, the crane plug won't go in far enough to activate. If I apply pressure to the plug while hitting the unity hot button it will run. It falls right out though because again, won't go in far enough. Not unity's fault, streamlight just wants you to buy their pressure pad. Really the only bad thing about it, but it was also why I bought it so, kind of a big deal.