PRESTA VALVES: Available in 33mm or 48mm, Non-Removeable Core. BUTYL RUBBER CONSTRUCTION: Ensures Excellent Air Retention and Durability. PUNCTURE RESISTANT: Thick Wall Construction Provides Protection Against Sharp Objects. PATCHABLE: Compatible With Butyl Tube Patch Kits. EXTENDED TUBE LIFE: Butyl Chemistry Engineered for Longer Life. FLEXIBLE FIT: Adapts Well Under High Pressure and Heavy Loads.