Fits CRC and most link cars using the tapered cone springs. CRC's new side springs are made unpainted music wire which is known for its high tensile strength and high elastic limit. Music wire can withstand high stresses under repeated loadings, and will continue to perform well under many normal cyclic applications. We have the pro-tapers in .45mm, .50mm, .55 mm and .60mm. They fit the CRC spring holders as well as many other manufacturers.