General Specs: AyA, Year 1969+/-, 12 Gauge, 7lbs 7oz, Chokes M/XF Serial Number: 266986 As shown on the AyA website: The Model Nº 37 is the most famous over-and-under ever made in the Basque Country, and at one time was the most expensive shotgun made in Spain. Patterned after the celebrated German Merkel, the Nº 37 was described by the American expert, Col. Charles. We have a good selection of used over and under shotguns for sale, from gun makers such as Baikal, Beretta, Browning, Investarm, Lanber, Laurona, Miroku and Winchester. ... AYA Yeoman Game/Sporting 12G SSTE MC over and under shotgun. £385.00 Yildiz SPZM Left handed .410 MC over and under SSTNE shotgun.