QUICKDRAW WTC PIPES
These pipes are very lightweight (12 ounces) and made of
steel, therefore they have excellent resonance. They feature a
tapered head pipe and a flexible coupling that virtually
eliminates pipe cracking. This coupling also makes it
extremely easy to adjust pipe length. They fit Quickdraws or
Zenoahs. They come in 90, 100, or 106 degrees, wrap to
center (WTC) or Deep Vee. All these pipes perform
identically, there is no loss or change in performance between
the different routing configurations.
( taken from the QD site :
http://www.quickdrawengines.com/sample_41Y/Page_40.html )