Bobro Engineering Lowrider BUIS
The Bobro Engineering LowRider sights are designed from the start to be an extremely low profile set of BUIS for nearly every purpose.
For example, many SBR owners have run into an issue with figuring out how to mount a set of BUIS on the upper and still fit their needed Lights, Lasers and Optics. The idea was to make it so that the Rear Sight was so low profile that there was almost no possible way it could interfere with optics and the Front Sight could easily be mounted under the front arm of the optic mount.
This keeps them out of the way, but can still be used in the even if the primary optic has a failure. This is just one application, where the Lowrider BUIS is ideal.