316 stainless steel tube

Pipe is generally more rigid than tube, and is usually produced in heavier wall thicknesses.

Pipe is specified by a nominal dimension which bears little or no resemblance to the actual dimensions of the pipe. 1" Schedule 40 pipe, for instance, has an actual OD of 1.32", a wall of 0.133", and an inner diameter of 1.049". Tube dimensions are actual dimensions.

Pipe fittings are sized to meet pipe sizes, but not tube sizes. A 1" schedule 40 nipple will fit correctly on a 1" schedule 40 pipe, but not on a 1" OD tube.