Good product from an excellent company - Crimson Trace LG-499 Laserguard, Green Laser Sight for Heckler and Koch

The vertical adjustment was almost correct. The horizontal adjustment was off a bit a impacted right it is an easy adjustment. But take your time to zero it. The adjustment screws have a nice click in small increments, so you can easily count the number of clicks. It is tactile not audible.

obviously you do not want to overtighten the assemble screws, but, after adjust the windage and elevatiion, I changed target and moved it farther away. The impacts were off. The screws had loosened a bit after 100 rounds. So, check these when zeroing this device. I am considering putting on a dab of easy removable Locktight.

The activation button is very sensitive. When you draw it turns on. Iam not a fan of that early warning green laser light.
I modified the sensitivity by adding a layer of Talon rubber grip material with a small hole punched out for only the little button.. You will need to add a bit more pressure with you middle finger to activate. I have it so that when I present and have a good grip it turns on to confirm sight alignment. A fractional second before trigger press with sight alignment.
This is personal and not for everybody.

The green laser emitter is very bright compared to a red one. Great for outdoors but very noticeable in low light.I prefer my red one in low light. But with the mod that I made this works everywhere with the green as well.