ScorpionSmarTUBE is the mountain bike specific inner tube that blends the innovative features of TPU (Thermoplastic Polyurethane), a specific formulation for the riders that are looking for the best balance between protection against punctures, weight and volume.ScorpionSmarTUBE is a one-of-a-kind inner tube: low weight and volume combine with a high level of reliability not available with an equivalent butyl tube.The perfect solution for marathon racers and trail and enduro riders that are looking for a lightweight, more puncture resistant and compact spare tube.NOTE: Not for use with rim brakes.