JS Technology Inc., Alpharetta, Georgia - contract supplier for military/government. As with the KAL/Proamerica sets above, the NSN number calls this a "small arms repair kit". I do not believe that JS Technology actually manufactured any of these pieces, but I've never been able to figure out who the OE supplier was.
Some say S-K, but that Kilness-type clip ring on the drive side of the head certainly doesn't look like any S-K ratchets that I own.
Fit and finish on these is fabulous. I think I have three of these sets - all appear to be unused. Really nice action on the ratchet - similar feel to the 2426 Wright.