I think I've seen this before somewhere but can't figure who the manufacturer was etc. Figured that someone here would know.....

I'm looking for a rear peep/aperture sight that attaches to the rear scope base (Leupold QRW or QR). I'd like to have the ability to switch between the peep/aperture sight and scope while in the field while retaining each sight systems zero.

Am I imagining something that isn't possible? Thanks in advance!!!