These are quality bus - Samson True Back Up Top Mounted Deployable Front and Rear Sight

These are SO much better and higher quality than any plastic BUS on the market, and at a decent price. Very solid, well machined, I'm more than happy. I did see reviews where a few people said, 'These are not for you if you need back up sights you need to deploy quickly'. That's rubbish. They deploy as quickly as any other I've used, but they will UN-deploy a bit slower because you have to press the button in that gives them their awesome rigidness and durability. Think about it. If you're DEPLOYING your BUS, chances are you're not going to have to UN-DEPLOY them unless your optic starts functioning again, which is unlikely. And even if it does happen, they're standard 50/50 co-witness for a lot of optics. Mine are paired up with an Eotech XPS, (yes, I'm bragging) and they're dead center. Anyway, I like them. Give them a shot.