A pup joint is a short pipe length used to extend or adjust the length of a drill string. It is also used to connect two components that have different thread connections. Pup joints are typically available in lengths of two, four, six, eight, and ten feet, although custom lengths can also be made. Pup joints are often used in the oil and gas industry to make minor adjustments to the length of a drill string, which is the string of connected pipes used to drill an oil or gas well. By adding or removing pup joints, drillers can adjust the length of the drill string to reach different depths in the well. Pup joints are also used to connect two components with different thread connections. For example, if a piece of equipment has a threaded connection that does not match the threaded connection on the drill string, a pup joint with the appropriate connections can connect the two components.