Extremely air-tight! Less air loss means having to inflate less often. Schwalbe's unique rubber mixture makes it possible. Extremely reliable! Each SCHWALBE tube is individually examined twice at the factory to ensure air-tightness. Special quality control that prevents unpleasant surprises. Standard Schwalbe valve length for both types is 40mm. In Schwalbe talk, the SV is presta and the AV valve is Schrader.