Cloud Defensive’s BATTERY JACK: Awesome Weapon Light Thingy

Cloud Defensive Battery Jack: an important factor in the reliability of the Cloud Defensive REIN
December 4, 2021  
Categories: Guns

CD’s “battery jack”. What is it, what does it have to do with the Cloud Defensive REIN, and why should you care? Allow us to explain!

One of the big problems with early pistol-mounted red dots back in the day was their vulnerability to the impact of recoil. Every time that slide moved, locked back, dropped back into place, etc., it was punishing the RDS. The same sort of thing holds true with a weapon-mounted light (WML). Each time that bolt cycles, the light absorbs some impact. This might not immediately or even catastrophically affect your light (it’s more of an aggregate/cumulative problem, typically), but it does affect it.  You may recall from some of our past social posts and interviews with Cloud Defensive guys that they did all sorts of research to understand how a WML’s guts respond to recoil, including some slow-mo filming through cutaways like you’ll see below. What they found was that many batteries (which often vary incrementally in size even among the same brand) piston back and forth, vibrate, or even rotate latitudinally under recoil.

Repetition of this rough recoil can wreak a ruinous response.

And that’s they put a shock-stop-hold-it-in-thingy into the REIN: the very battery jack we mentioned earlier. And that’s a good thing, too, because “shock-stop-hold-it-in-thingy” not only takes a long time to say, the acronym is not really marketing-friendly. 

Cloud Defensive REIN FDE

A Cloud Defensive REIN FDE: courtesy of Fifty Shades of FDE, of course.

Anyway, here’s what they say about it. Check it out. Scroll further down to find the video. 

CD’s Battery Jack

via Cloud Defensive

The Battery Jack. We don’t talk about this as much as we should. It exists because guns experience recoil. That force is translated through your weapon light. And through your battery. The battery has X amount of mass. And thus, kinetic energy is created with each shot.

Historically, kinetic energy is essentially absorbed by the battery springs at both ends of the light (head and tail). This can lead to battery damage as the battery is moving violently inside your light during hard use. And mechanically speaking, when things move, they wear out faster. Not good.

Cloud Defensive battery jack

The Battery Jack is an important factor in the reliability of Cloud Defensive weapon lights

The Battery Jack was created to render this problem non-existent. In function, it simply applies pressure that shoulders the battery on an insulator in the light head. Thus, the battery is fully supported at both ends. And just like that, you remove all that stress from both your springs. The system is instantly rock-hard. No battery bounce. No battery damage. You can go to hell and back with that light and the battery will look as good as new. A simple concept that drastically enhances the service life of the system and reliability as well.

Cloud Defensive REIN FDE: mounted up, protected from recoil, ready to work.

Cloud Defensive REIN FDE on a Victory First LWRCI blaster: mounted up, protected from recoil, and ready to work.

REIN: Real Talk

The REIN is a superb weapon light and one of our most highly recommended gun accessories – and if you’re one of those who’re running dual light/IR rigs and are worried about real estate on the rail, stand by. They have a whole new family of switches on the way. 

⇒ Get Your Own REIN Now

A Cloud Defensive REIN FDE model and another in the original black

A Cloud Defensive REIN FDE model and another in the original black: “black and tan”, courtesy of Victory First’s Matt Jacques.


More to follow!

Think, train, and be dangerous. 

Love, Us

Enjoy what you’re reading? Sure hope so. We like writing stuff. We also like to eat, pay bills, and tip the occasional dancing mom! 

You can support the site by making your purchases via one of our links.

Recommended Reading

Get banged on the regular, sign up for the newsletter!

Mad Duo

Mad Duo

About the Author

The Mad Duo are the most renowned, scholarly, door-kickingest action figures since...well, ever. They, their wretched minions and other abject flunkies are an improbable (and awesome) tale unto themselves. Read more about them here.


Submit a Comment

Buy Me a Coffee at

Popular Articles

PSA Uppers, Lowers, Optics and More! 4th of July.
Celebrate July. Buy more, save more. Up to 30% off. Forloh.
Lone Wolf DAWN. Parts for Sig Sauer P365 30% off. back Breach-Bang-Clear

Find what’s in stock, and where, and compare prices. 

⚠️ Some hyperlinks in this article may contain affiliate links. If you use them to make a purchase, we will receive a small commission at no additional cost to you. It’s just one way to Back the Bang. #backthebang 

Get Patched In

Wretched Minion Patch