X-Treme Duty Top Half of Ring with Bubble Level | Precision Shooting Component, Compatible with 30mm or 34mm Steel Rings, Available in 4 & 6 Screw Patterns

The level is very well made and is easy to install in place of the previous top half of the ring. I've used mine for just short of two months now with about 500 rounds downrange, and it's worked as advertised, with no breakage and no tendency for the bubble to split into multiple bubbles.I was concerned that it may be difficult to see with middle aged eyes when mounted on the rear ring (and it would be hard to see if mounted on the front ring with the elevation turret in front of the level). However that has not been the case. It's easy to look up slightly and ensure the bubble is centered when setting up the shot. the level is blurred slightly with my middle age accommodation issues, but the lines are still visible and it's obvious whether the bubble is centered or not. That's a good thing as this design is much less exposed than a level that is offset to one side of the scope (but could be mounted forward of the turret). Envisioning a line between the rear of the eyepiece and the top of the turret makes it clear that dropping the rifle in a manner that would succeed in breaking the level, would create far greater problems for you than a broken sight glass in the level.If you want to get full utility out of it, care needs to taken to ensure that the ring half/bubble level is mounted so that it is level when the crosshairs are level. If you've already properly leveled the scope in the rings, you just need to verify the ring half is level when the vertical crosshair is parallel to a plumb line suspended far enough in front of the scope to see at low magnification, and snug the screws up for the ring half while maintaining a centered bubble. If not, you'll want to level the rifle, and then while maintaining a level rifle, level the scope in the rings with the plumb line and snug up the front ring to secure the scope in place, before leveling the rear ring half with the level and snugging it up as well. Then torque all 8 ring screws evenly and recheck that everything is level. This presumes a high quality scope where the reticle and scope adjustments are in alignment with each other.If there is a downside it's in the $78 purchase price for a bubble level ring half. But then if you're buying one you've already ponied up $150 or more for a set of Nightforce rings and should be used to the NF sticker shock by now.As for some of the negative reviews:I noted that the level pictured was the one with the angle indicator mount, not the basic model that was discussed in the text. Consequently, I was able to correctly determine I was ordering the basic model that I wanted. I guess that illustrates the value of actually reading the description to overcome a mistake by the person posting the picture on the website. To be fair to both sides, the incorrect picture was confusing, and the picture on the website is now correct, showing the basic bubble level with no angle indicator or mount for the angle indictor. In any case, the picture now matches the item and less actual reading is required. None of that should however reflect negatively on what is an excellent item.

Perfect fit- great location for a level bubble.I have the vortex ones on other guns, but this one is far the best

Nightforce is higher end stuff but never disappoints. Very useful ad on to your rifle.

Not much to say it works and it looks good low profile i like it.

Great level and flawless fit on NightForce rings! Awesome NightForce quality...love it!

nice addition to my night force NXS...

Fits well

Excelent product