A thread protector is used to protect the threads of a pipe during transportation and storage, can be used on Casing Pipe, Tubing, Drilling Pipe. 

They are generally manufactured from plastic or steel and can be applied to the pipe manually or automatically (by machine), and they are used frequently in the oil and gas industry to protect pipes during transportation to the oil and gas fields. 

There are mainly 2 categories of protectors used commonly: HDPE Plastic Thread Protector, Metal Thread Protector. 

Metal thread protectors can be cleaned and re-used, while plastic thread protectors are often collected and either re-used or recycled. The heavy duty HDPE Plastic thread profile prevent all contact between the steel bumper & the thread connection thereby eliminating possibility of bi-metallic corrosion. Metal thread protectors are available in sizes: 2-3/8, 2-7/8, 3-1/2, 4, 4-1/2, 5, 5-1/2, 6-5/8.