silver pen tire pressure gauges this pen can be used for testing pressure of car tire(tyre).when you compare the pressure from testing result to standard value,you will know whether the tire pressure is over or not. it can awake the tire pressure when you drive on subway. it can used for car ,bike and other tire(tyre) size:140mm x 10mm (dia) colors: silver plated colors PSI:5~50PSI(in normal condition,our car tire pressure is about 36~40 PSI ) accuracy:+/-1.5PSI Weight:16g/pc