Alpinestars T-SPS WP Jacket The T-SPS Air Jacket offers riders a lightweight, waterproof jacket with a 600D reinforced polyester main shell and removable thermal liner. Vents at the underarm are shielded from the elements and can be used to tailor the flow of air. Add the unobtrusive thermal layer when your shred session takes you deep into the cool night air. The T-SPS WP jacket includes Alpinestars' Nucleon Flex Plus elbow and shoulder armor, which is well-matched to this warm weather piece of riding gear.