Continental Bicycle Tube with 42mm Presta valve. The Continental quality road inner tube is a must have cycling essential for 700c bike wheels. This new Continental Tube hose program makes it even easier to find the optimum hose for your needs. The very clear and user-friendly hose system was perfectly adapted in size, design, valve type and length to the respective tire sizes and applications. Shorter valve inner tubes are ideal for wheels with rim depths of 24mm or 30mm but are not ideal for wheels with rim depths of 40mm or above (as the shorter valve would not extend out of the rim valve hole). Presta valve tubes are most commonly used for road wheels (700c) and on a few MTB wheels as the valves are thin, whereas Schrader valves are more commanly found on MTB wheels as valve is larger and won't fit through 700c rim valve holes.