The Merkur Progress is a wonderful razor the design has been around since 1955 and is still made today so these can be bought brand new. They are a two piece design so to change the blades the top cap needs to be completely removed. The adjustment dial ranges from 1 - 5 there is no "click" you just line the dot on the handle with the numbers on the adjustment dial.
The Gillette Fatboy Adjustable Razor
This razor is iconic among the adjustable razors, if you are going to start collecting adjustable razors this is a must have, it's a wonderful heavy tto adjustable.