Check the listing for details. 4pc Heated Bed Springs Die Springs Light Load Compression Spring for 3D Printer. Condition: New. Listed at 6.22 USD. Loading Grade : Light LoadHole Diameter (OD) : 8mmRod Diameter (Inner Dia) : 4mmFree Length : 25mmProduct Name : Die Spring; Rectangular Section. Die springs are primarily used in die machinery.For die springs, yellow color here represents that the loading grade is light load.However, because die springs are well suited for high stress applications, they are also suitable for a variety of other applications as well.Hole Dia: The Diameter of the Hole on the Mold ,i.e.the Outer Diameter of the spring.Rod Dia: The Diameter of the Rod that is to be inserted into this spring, i.e.the inner Diameter of the spring. Colour: yellow、blue(Random)Package Contents:4*Die SpringOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.