Flown Crewman Optical Alignment Sight (COAS), flown to the surface of the moon on board the Apollo 15. Sight measures 8.75 x 4.25 x 3, weighs approximately 1.5 pounds, and has an Autonetics—North American Rockwell metal plate attached to the lower portion which reads: “Sight–Optical Alignment–LM; ME331-0018-0025; Ser. No. 06359-0768 BKA,” with a smaller Autonetics label affixed below the optics. This sight was used by Dave Scott during the mission and was secured by its mount above the left window of the lunar module. Accompanied by an incredibly detailed 2014 two-page letter of authenticity and explanation from Dave Scott, which reads, in part: “I hereby certify that the ‘Crewman Optical Alignment Sight’ (COAS) included with this letter was installed in the Lunar Module ‘Falcon’ during Apollo 15…The COAS was used by the Commander (CDR) for rendezvous, docking, star sightings, and horizon alignment during the Lunar Module phases of the mission…This LM 10 COAS has been in my personal possession since returning to Earth.” In fine condition. Arguably one of the most impressive and important pieces of precision lunar module-flown equipment ever offered.