We all know the famous Bulova tuning fork movements and the Omega-branded versions it powered – the f300Hz. But did you know IWC also used the same movements? That’s right, the fish crown brand also introduced its own tuning fork-powered watches, the reference 3403 and the caliber IWC 150 (ESA 9164). Back in the 1970s, this was one of the most expensive tuning fork watches money could buy, at a whopping 1,000 CHF. For reference, a Submariner 5513 would set you back roughly 230 USD in the same decade. The case is developed from a proprietary hard steel alloy (Durci) with a Vickers hardness between 1,000 and 1,500.The watch features a gorgeous blue-ish sunburst dial with matching white and blue hands. It also has the original integrated bracelet with a signed IWC clasp. I recently swapped the date wheel for a white one. On top of offering better visibility, the blue wheel that came with the watch had some teeth worn, meaning it wouldn't flip over sometimes. I'll include both date wheels, as it can definitely be fixed by a skilled watchmaker. **Details & More** **Condition:** Good. Dial and bracelet look pristine. Case has some wear on the side and back, which is very common with this material. **Case size:** 38 x 42.5 if you count the lengthy middle link that’s part of the case. **Movement:** IWC 150 (9164), 12 jewels, 300 Hz. **Other information:** * The bracelet will fit a wrist of up to 6.75 inches. **Price:** Asking 2,100$ (1,945€). Add 80$ for worldwide shipping via UPS or 35€ for GLS shipping in Europe. [Pictures](https://imgur.com/a/BgcpGtP) [Timestamp](https://imgur.com/a/J2HXI08)