Simply remove the wheel, brake caliper and hub to insert greaser tool and use grease gun to pack wheel bearingsDesigned to service Polaris 40 mm ID wheel bearings without removing the wheel shaftHigh quality CNC machined with precision drilled grease channelQuick and easy way to extend the life of your wheel bearingsWorks with Polaris bearings 3514635 and 3585502, EPI bearings WE301016 and WE305502 or any equivalent.