SERPAGS
Expert
I have the 6" . I beleive thats the longest.
blackattak
Expert
I went on the bergstrom website & they help you decide. Apparently cener studding will push more so they recommend more carbide 144-192 studs would normally take the Type III 6" one but it looks as if I will have to go a little more The Type IV is a 8" one. Even comes 10" but not planning to go there. 
