The 15B and 17B are Fluke meters that are made for the Chinese markets, only. You can't even find them on the Fluke website (you can look up the manuals, though).
IMHO, the 15B and 17B are in the same line as the 113 - 117 series of meters. They are a bottom tier line offered by Fluke that are meant to be more competitive with other brands, but their specs/warranty are not at the same level as the 175/177/179 or 80 series. Just my opinion, but you'd probably be better off searching for competitor's products if looking at these. You'll be paying a lot just for the "Fluke" name, but not getting the same level of robust/high performance product that made their reputation.