This is a modern day version of something called a polemoscope. It was first used in the 1700′s at the opera in order to discreetly look at that cute girl or guy in the audience without their suspecting.
This one is a fully functioning model. You look in the end as though observing the rockers on stage, but all the while you are ogling the cutie to your side in the audience.
Museum, Other Ophthalmic Objects
