It is handmade in Hong Kong, therefore I have to get one. It was made in a factory in Tuen Mun, the town where my father was living. The f-stop is 138 so the multiplier factor is 4.65 using a light meter at f-64. The extra brass mechanism is the shutter release. It is very small and compact. I bought the Vermeer 6x6 before I discovered the Zero Image. Refer to Vermeer 6x9 Pinhole for my shooting procedure.