T cells and B cells differ in the form of the antigen they recognize, and this affects which antigens they can detect. B cells bind to antigen on invaders that are found in circulation outside the cells of the body, while T cells detect only invaders that have somehow entered the cells of the body.
ABS, DWV, Solid or Cell Core sewer pipe. The solid pipe is composed of ABS at 99% while the cell core is composed of a cellular foam between 2 layers of ABS which makes the cell core pipe lighter.
http://www.plumbersurplus.com/images/prod/5/Zurn-Q4PC500XRED-rw-48919-13175.jpg. PEX pipe is a semi-flexible water-supply pipe that is useful for many applications. From general plumbing to radiant heat floors, PEX is a go-anywhere plumbing solution. Bending PEX tubing is a snap, but you have to remember to strap the tubing into place so the bends will stay where they need to. You can also use PEX hangers to accomplish this.