What is the Difference between Pup Joint & X-Over / Crossover?

What is Pup Joint? Tubing joints are generally around 30 ft (9 m). The short length of the Tubing Joint is called Pup Joints; it is used to adjust the length required for space out for completion string. Pup Joint is same as Tubing Joint the Size (2-7/8”, 3-1/2” 4-1/2”), Threads (EUE, Vam Top, JFE Bear, etc), Grade (J-55, N/L-80, P-110), weight (6.5 PPF OR lb/ft, 10.4 lb/ft, 8.7 lb/ft) are same as Tubing Joint only difference in Length (from 1 ft up to 20 ft) Pup joints are also known as saver sub, spacer, and pup X-Over means Crossover: A crossover sub is a mechanical part with threaded connections. It is used to connect threaded components that have different sizes or have different thread characteristics. Crossover subs are typically found in the drill string between the drill pipe and drill collars or at other points in the drill string. A crossover is a one-piece tubular section used to join or change two different components with different sizes of tubes, or types of connection. These components can be casing, tubing, drill pipe, or combination.