Up for sale are a set of rider-quality Shimano 600 nutted brake calipers. VeloBase lists these as from 1975-77. Definitely not showroom quality, but anodized finish on the arms is in excellent shape. Some hardware, particularly the springs, has some corrosion, the cable adjusters don't match, and one of the QR levers has lost its plastic cover, but mechanically they're overhauled and in very good shape. I'm including the original brake pads, marked "Dura Ace," though they're worn as the holders are cool and the hardware is quite nice. Reach, as marked on the rear, is 57mm max (47mm min). Price is $35 shipped in the CONUS. PayPay to lerner dot n at gmail dot com.