On the T525 starter diagram, what is the part number for no. 4?

Looking at the Husqvarna drawing that's coming up as the spring. However this is only up to s/n 20202609488. 587 87 59 01 - Spring - https://www.lsengineers.co.uk/spring-genuine-husqvarna-part-oem-no-587-87-59-01.html