I bought mine from the local tire dealer/repair that services tractor tires. Dont' buy a cheap one. Buy the specific gauge for liquid because they have a stainless internal spring. Calcium filled tires will corrode your cheap gauge and you will be buying a new one every year. I bought the same kind the mechanics use themselves ( think it was around $10-$12). It was made in USA...TSC was china. Even with the stem on top ,there is moisture which will enter your gauge..whether calcium or any liquid-filled, it will ruin your gauge eventually