50 years old — Longines — Ultronic Tunig-fork — Cal 6312 — Vintage 1976 Smooth humming sweep, sharp 1970s geometry, mineral crystal for daily wear. Collector Notes & Dating Longines Ultronic in stainless steel with the high-grade Longines cal. 6312 (ESA 9162) tuning-fork movement. The 37 mm angular tonneau case wears slim and modern; silver sunburst dial with applied baton markers, baton hands and framed date at 3 with quickset. Signed crown present. Crystal is mineral glass. Fitted on an aftermarket steel bracelet. Cal. 6312 is a 12-jewel, ~300 Hz tuning-fork caliber from the ESA 9162/9184 family, designed under Max Hetzel (of Bulova Accutron 214 fame) and often dubbed the “Rolls-Royce” of tuning-fork movements. Movement no. 52956640 is recorded and dates to 1976. A clean, wearable slice of early electronic Longines with that unmistakable humming sweep. SPECIFICATIONS Movement: Longines 6312 (ESA 9162) tuning-fork, 12 jewels, ~300 Hz, quickset date. Dial: Silver sunburst, applied batons, baton hands, framed date at 3. Crystal: Mineral glass. Case: Stainless steel, angular tonneau; snap back; light honest wear. Size: 37 mm without crown. Crown: Signed Longines; push/pull. Strap/Bracelet: Aftermarket stainless-steel bracelet. Water-Tightness: Splash resistant; not pressure-tested. Box / Packaging: Secure travel watch case. A wearable early-electronic Longines with premium tuning-fork tech and timeless 1970s styling. What’s Included Box/Case: Travel watch case. Every watch undergoes functional, timing, and daily-wear checks according to vintage standards and is sold ready to wear. Pictures are part of the description and are from the Actual Item.