Suitable for example:
For newer Husqvarna and Jonsered chainsaw models with a "collar" on the blade nut, see the product image and the bottom of the nut (the nut on the right side in the picture).
Suitable for example:
Husqvarna345F, 345FX, 345FXT, 545F, 545FX, 545FXT
JonseredFC2145
Replace the original numbers:
Husqvarna 502291101, 5022911-01