Instead of using two wrenches, the Rolling Mavericks CNC rear axle blocks only require a 10mm open-ended wrench to tension your chain because the locknut is eliminated. The scales also make it easier to align the wheel and chain. These blocks require only one wrench instead of two, and you don't need to slide the wheel against the tensioner bolts as you have to do with the OEM blocks. The tensioner bolts hook into the recess of the axle blocks and slides the axle forward or backward as you loosen or tighten the bolt. The visible scales on these anodized 6061-T6 aluminum CNC machined blocks make aligning the wheel and chain much more effortless. The square nut is a tool to remove the OEM block from the axle and to help you install the new block onto the axle. CNC-machined 6061-T6 aluminum, lightweight and durable Anodized surface finishing Scales on both sides of axle block for easy adjusting It makes wheel changes and adjusts easier Easy to install Package includes: 1x Set Axle Blocks Chain Adjuster Square' removal tool' nut Fitment The blocks are for 20mm axles. KTM: 2005-2012 KTM 125 SX 2005-2016 KTM 125 EXC 2017-2019 KTM 125 XC-W 2007-2008 KTM 144 SX 2009-2012 KTM 150 SX 2017-2021 KTM 150 XC-W 2005-2009 KTM 200 SX 2005-2016 KTM 200 EXC 2005-2012 KTM 250 SX 2005-2021 KTM 250 EXC 2005-2021 KTM 300 EXC 2006-2012 KTM 250 SX-F 2006-2021 KTM 250 EXC-F 2011-2012 KTM 350 SX-F 2011-2021 KTM 350 EXC-F 2008-2012 KTM 400 EXC 2005-2012 KTM 450 SX-F 2005-2021 KTM 450 EXC 2012-2021 KTM 500 EXC 2007-2008 KTM 505 SX-F 2008-2011 KTM 530 EXC Husqvarna: 2014-2015 Husqvarna TC 125 2014-2016 Husqvarna TE 125 2017-2019 Husqvarna TX 125 2017-2021 Husqvarna TE 150 2014-2016 Husqvarna TC 250 2014-2021 Husqvarna TE 250 2014-2021 Husqvarna TE 300 2014-2015 Husqvarna FC 250 2014-2021 Husqvarna FE 250 2014-2015 Husqvarna FC 350 2014-2021 Husqvarna FE 350 2014-2015 Husqvarna FC 450 2014-2021 Husqvarna FE 450 2014-2021 Husqvarna FE 501