Tube Duro 700 x 19c/23c 48mm Standard Presta/Valve. Tube Duro 700 x 19c/23c 48mm Standard Presta/Valve. Tube Duro 700 x 19c/23c 48mm Standard Presta/Valve. We carry over 3,000 bicycle parts and accessories. If you have any questions about any of our parts, please send us an email. sold 1 each