1. Free length: (a) total length, (b) full length, and (c) length from the hook.

2. the control diameter: (a) outer diameter, (b) inner diameter, (c) the inner diameter of the casing.

3. the wire size "wire diameter".

4. the material (type, grade).

5. Number of turns and direction of rotation: (a) Effective number of turns and total number of turns (b) Right-handed or left-handed.

6. the form of the end.

7. the load inside the hook.

8. load rate, deflection, pounds per inch.

9. the maximum stretch length.