1. Tube Diameter: This is typically expressed in millimeters. The 5X8 tube will have a 5 mm outside diameter and an 8 mm inside diameter.
2. Tube Length: The tube length can vary and it is typically expressed in meters.
3. Wall Thickness: This is typically expressed in millimeters. It is generally the same as the inside diameter of the tube.
4. Color: The tubes may come in various colors and can be custom made. Some of the common colors are black, yellow, orange, green and red.
5. End Form: This is the shape of the tube end. They can be round, square, rectangular, or any other specific design.
6. Material: The tubes may be made of various materials such as steel, aluminum, plastic, or any other composite material.
7. Surface Finish: This is the type of surface coating, such as anodizing, that is applied to the tube.
8. Strength: The tubes also have a strength rating, such as yield strength, tensile strength, and fatigue strength. This rating is used to determine the maximum stress that the tube can withstand without cracking or breaking.