The Variant 3 ballnut is a tricky one. As a client you need to keep in mind that you need the mountingblocks Spannblock 1 or 2 to mount it in. Or you could make your own. Anyway without the block there is no pretension on the nut and thus it cant be used. The nice thing is that you can also mount wipers in this nut to keep dirt out further its the only ballnut available in all pitches.