Stock Photo: An oil well pump jack in northeastern Colorado, showing motion of the pump, the end known as the 'horsehead' (left side), walking beam, crank, and counterweight. A pump jack is also known as a pumpjack, a pumping unit, a grasshopper pump, and a jack pump, among other names.

Stock Photo: 4316-3308 An oil  well pump jack in northeastern Colorado, showing motion of the pump, the end known as the 'horsehead' (left side), walking beam, crank, and counterweight. A pump jack is also known as a pumpjack, a pumping unit, a grasshopper pump, and a jack pump, among other names.