That design is sadly discontinued, I believe they were made by Dreier brothers who are now out of business. I have a HS16 and can confirm that it is one off it the best designed high-tension hacksaws ever made. Still see them on eBay
The patent number on my HS16 was applied for in 1979 by Easco tools, they must have Dreiers Brothers prior to that date as Dreiers had already patented the tensioning device