KTM EXC - EXC-F - XFW PDS  2017 to 2024 models
60mm ID x 230mm Length.
For more aggressive and faster riders a variable rate spring is superior. The PDS has plush advantages but when using all the rear suspension the variable rate spring out performs. The variable rate will slow the bottoming event down so the shock does not go so deep into the stroke. When the rear goes too deep it  allows the spring to over power the rebound circuit creating a rear end kick. If you do not ride fast then you likely do not need variable except an emergency situation. If you hit an obstacle at too high a speed then the variable can save you.