10, 13

I don't know as these wrenches should be counted among my favorite tools, but since the most common sizes for nuts and bolts on an air-cooled VW are 10 and 13 millimeters they deserve some kind of mention. If you work on Type 3s or late buses, you really should get an extended 10mm like this one for easier loosening and tightening of the distributor clamp. 1/2" and 13mm wrenches are basically interchangeable, fyi.