The Bike-It Pressure Alert Valve Caps are a simple but highly effective solution to one of the contributing factors in poor fuel consumption, uneven tyre wear and more seriously accidents.Simple but effective valve capsConstantly monitor tyre pressureColour-coded display alerts of low pressureSupplied individuallyThe Bike-It Pressure Alert Valve Caps constantly monitor tyre pressures and alert you of pressure loss. Each cap has a minimum pressure rating and when tyre pressure is above this minimum rating a green ring shows and all is well. If pressure drops below the minimum rating a red ring shows - time to check pressures and inflate.Simply select the lowest PSI limit that's nearest to your bike/manufacturers recommended tyre pressure.Options Available Are:PSI Limit 28 / PSI Range 29 - 30PSI Limit 30 / PSI Range 32 - 34PSI Limit 34 / PSI Range 35 - 37PSI Limit 40 / PSI Range 41 - 43