Now lighter than tubeless, Pirelli says this is the easiest way to reduce rolling resistance...assuming you're using their tires.

SLiME Smart Tubes are bicycle inner tubes that contain hole-sealing slime. If you’re a mountain biker, then you are no doubt aware of the increasing popularity of tubeless tires.

Bicycle inner tubes that contain a small-puncture-sealing slimy liquid may not be a new ... can get a Protek Max to fit their tire. It is available in sizes of 700 x 35-47c (200 grams) and 26 x ...