ROCRIDE BIKE TIRE PRESSURE GAUGE Is Made Of Stainless Steel For Durability. Measurements Are Easy To See On The High Contrast Black On White Readout. To use the Presta Valve Adapter thread the adapter onto your presta valve after loosening presta valve opening, then just press the gauge onto the adapter for an instant reading. External threads on the adapter are for use with a pump and are not used with this gauge.