This lens doesn't fall into the heavyweight category that my recent medical scare has finally convinced me to purge, but it's hanging around and I don't use it so may as well find it a new home.
Here's one I've never seen or heard of before. The trim ring calls it a Tokron (long "o") and it's marked as being made by Yamasaki. Since it came on a Toko (also long "o") FL-452 4x5 I bought last year I believe it's likely a custom naming done for Toko. Given its size and maximum aperture it's probably a Tessar so will cover 4x5 with a bit of movement. The glass is clean and clear but there's a small amount of coating damage on the inner surface of the rear cell from someone's overly aggressive cleaning. The shutter operates smoothly, the speeds sound appropriate, and the retaining ring is included. It mounts in a Copal 0 hole. The filter size appears to be 40.5mm. There are no caps but the 42mm and 31.5mm front and rear caps from my 100mm Symmar-S fit perfectly. This is quite a lightweight lens at 138 grams (4-7/8 US ounces) with the retaining ring, just 2 grams more than the 150mm f/6.3 Fujinon-W in Seiko 0 and 10 grams less than the 150mm f/5.6 Xenar in Copal 0.
The Seiko shutter's operation differs from a Copal in that it must be cocked to open it for focusing. Cocking is via the lever with the black-centered knob, and opening/closing is done with the nearby lever with the slightly smaller all-silver knob (this one is almost diametrically opposite the release lever).
Fingers and wedding ring not included.
My asking price of $110, basically what you'd expect to pay for a shutter alone, includes insured shipping to the PayPal-verified US address. PayPal G&S is fine. International shipping is crazy-expensive even for something this small and light so I'd like to start out offering this to US buyers only.