The GAD1 and the GAD2 have the same features. The GAD1 has a smaller diameter fork and will only accept the 1.580″ and smaller I.D. docking rings. If you have a Pro sled with a 1.500″ post size and think you will be upgrading to a 2″ post in the future, I would suggest buying the GAD2. That way you will only need to purchase a different size docking ring. You will need the GAD2 if using a post size larger than 1.580″. GAD2 size docking rings listed largest to smallest. MK-V 4 stage post size of 2.125″, 2.00″, 1.860″, 1.800″, 1.790″, 1.685″, 1.580″,1.500″ 1.495″, 1.477″ The O.D. of all the rings are the same size. All GAD2 and HBB now come with blue Anodized levers and brake knob. Call if you do not see your post size listed.