I have 3 casket sets, two of which will cover 4x5 and 5x7. The third is a puzzler. No brand name, bayonet mount, waterhouse stops (has a complete set in the original purple-leather-lined case!), and 6 elements. I am having a flange made for it right now so have not been able to test it. I do know that the barrel is labeled No 6 which I hope means it will cover 8x10, as my other sets are No 3. Each element is paired with a sleeve numbered 2,3,4, and 5. Numbers 6 and 7 have no sleeve and appear to be for the back of the lens since they are gunmetal grey and the other parts are shiny brass. They are nearly 6cm in diameter, so quite large, and no indication of focal length. Of course no instructions.
Anyone care to speculate? And does anyone think it may cover 8x10?