A "Bespoke" hat, is basically a custom made to the client's specifications. You pick your hat body (some based on weight, stiffness, fur content, etc.), and it's color, the trim style for the edge (bound, welted, raw, etc.), crown height, ribbon trim, etc. The hatter should measure your head with the conformature and then use the conformer when they are making the hat so it is "custom fit" for you. A "non-Bespoke hat" is basically an "off the rack" and you don't get any options to change the felt, ribbon, etc. Most are pre sized (7 1/8, 7 1/4, 7 3/8, etc.)..but the hatter can "fit" you by steaming, stretching, and also blocking the style of the crease or pinch. I call these "semi-custom" in that the hatter will fit it to you. Art was a "bespoke" hatter, you chose the felt, ribbon, crown and brim dimensions, etc. Optimo hats I've had (probably 15 felts, 6 straw)..some where "off the rack" and others were simply sized custom for me (they have my measurements on file). Their hats are excellent, can be sized for you..and shaped to your liking...but they basically "pre make" the hat and then tweak it for you. It is close as you can get to a pure "bespoke" hat.