It looks like that is a nicely made valve, buy it appears to be made of brass, which unfortunately contains lead.
Many prefer to have only copper, stainless steel, and lead free solder contact their product.
Valves usable with a Bokakob type still head, made of stainless often sell for nearly $100. Even so some of these use a packing material which might come in contact with the distillate.
My valve uses no packing, and is 100% stainless steel. The flare style connection assures nothing but copper and stainless touch the product.
This is a non-production, quality, home-shop made valve. The through flow opening is .275 inches, and will couple with 3/8" OD copper tubing.
I would consider an offer of $300 for 10 valves.