If you have some Apollo Moon Exploring toys you may have the rectangular silver double reflector gizmo seen here in this blister on Worthpoint.
Well, here's the story of the real thing, the Lazer Ranging Retro Reflector or LRRR. Enjoy!
Kevin has kindly pointed out that the toy is a miniature of the Apollo Seismometer and not the LRRR! Doh! Thanks Kev. I should have gone to Specsavers!