John Lofgren Monkey Boots Shinki Horsebuttt - $1,136 The classic monkey boot silhouette in an incredibly rich Shinki russet horse leather. 
Grant Stone Diesel Boot Dark Olive Chromexcel - $395 Goodyear welted, Horween Chromexcel, classic good looks. 
Schott 568 Vandals Jacket - $1,250 The classic Perfecto motorcycle jacket, in a very special limited-edition Schott double rider style. 
It's actually "Sterkowski", with an "i", and here's a link to their website, specifically the page that shows their version of these "vintage biker/duty" caps. You can shop around, but the prices seem to be consistent between their website, Etsy, eBay, and so on. I don't own any of their caps or hats yet myself, but I've read good things about them and they appear to be very reasonably priced. Generic sizing, i.e. "S, M, L, XL", but if you can live with a cap that might fit a little looser than you'd like I think they're good value for the money.
I attempted a little online research, but didn't turn up much. From the 1930s through the 1960s these were known as a "Mechanic's cap" and were usually provided as part of the drivers' uniform. At some point during the 1950s they became popular among the "greaser" subculture, which is why they're often referred to as "biker" caps. Further attempts using the search term "mechanic's cap" led to a number of websites that made reference to the A3 cap worn by Air Force mechanics during World War II, but those are more like an unstructured ball cap with a long brim/bill.
This is a picture of some truck drivers back in the 40's I think. Even the truck drivers dressed fairly nice and I like the hat wear. What kind of hats are these and anyone know where I can get one? Other drivers in this era I believe wore fedora's and the guy at the end seems to be wearing probably a pork pie..not sure.
