We did a recent search on Qwan Din (Quan Dim), and found several companies selling “quan dim” (also seen as “quam din”, and correctly as “qwan din”) poles. In every case these are 100% fake. One of the companies is selling cheap laminate poles for $89.95. We sell the same pole for <$40 and warn people on the site that they are cheap and break easily. This other company touts them as quan dim wood and of excellent quality. Beware. We found at least 3 companies selling fakes, albeit one appears to just be ignorant as to what Quan Dim is because they list it as Quan Dim and Oak on the same page.
“Qwan Din” (“Quan Dim”) originates from our site, Everything Wing Chun. 
Buick Yip is the maker of these poles and we were the first to bring it to the world at large. There is no other source of Qwan Din poles, period. Buick gets this wood from old boats, piers, and the like. You can’t really find it on the open market anymore. Every reference on the web to Qwan Din pulled or copied that information from Everything Wing Chun’s store, period. Do not believe anyone selling you Qwan Din (or various spellings of).
There are other companies that use 
similar woods (an Indonesian species) for flooring and furniture, again most is salvage from old boats. You can tell if the wood is Qwan Din, usually, by the coloration. The wood can turn dark brown, almost black (as if it has been burned) from exposure to air.
Qwan Din is a heavy dense wood that is commonly used in making oars, like the long oars in the sampan, and it can be put into water permanently and will not rot. They are also heavy and flexible (imagine the long oars rowing against water constantly).
According to Wing Chun legends, the martial art was partially updated during the time its practitioners were part of the Red Boat Operas. This is the period of time in which the long pole was added as a weapon into the Wing Chun system. Considering these boats used long poles made from Qwan Din (Quan Dim) to help with their movement and navigation, we believe this is the wood of the original Wing Chun Lum Dim Boon Kwan (Six and a Half Point Pole, Dragon Pole, or Long pole).
There are other good woods for poles. Qwan Din (Quan Dim) is a very good wood, and thought to be the original, but others also make great poles. Check out all of our poles, including Qwan Din (when available) here.