You get what you pay for - Holosun Paralow HS403B 1x20mm 2 MOA Red Dot Sight

PROS: Affordable, easy to use, easy to zero, good range of brightness settings. Includes both a low profile and lower 1/3 mount, as well as a battery. The turret caps can be used to make windage/elevation adjustments.

CONS: Adjustment turrets are unprotected from drops/impacts, elastic/rubber lens caps pop off very easy, durability/reliability are questionable at best.

SHORT STORY:
Great affordable red dot. Would recommend for a training/range only gun/plinker or airsoft. If you keep your weapon in a hard case/safe and only shoot static ranges, this could be a good option.

NOT for duty use, field use, self-defense gun, or anything you'd trust your life to.

LONG STORY:
Figured I'd grab one to try out Holosun and not have to over-commit since it's cheap enough.

I had it mounted on a Stribog SP9A3 that I'd like to be a PDW/PCC build at some point but is range only for now. Kept it in a Vertx Commuter 2.0 Sling Bag.

I guess when I'd put it down, it was landing on the top/elevation turret and eventually hit hard enough to depress the turret into the optic body. The cap couldn't be removed but the optic itself still functioned.

I did not confirm zero after the damage since Holosun was replacing it under warranty. It took a few months but it was easy and at no cost to me, so I was happy about that.

The reason this happens is because the turrets are not recessed and they are not protected by the body in any way. They protude a good distance for something that delicate.

Holosun does have better models with stronger housing materials and integral design features that protect the windage/elevation turrets. I'd recommend paying a little more for one of those options and have that increased durability/reliability. Models like this one are part of what brings Holosun's reputation down from their higher quality optics.

Overall, like I said, I got what I paid for and Holosun's warranty dept. took care of me, so I'm not upset. Hopefully this information helps you make the right purchase choice for your needs!