My Nitro Gears are "Thin" 456. Purchased from ECGS.
I originally did not plan to run a front locker, So I purchased the thin ring. I ended up getting the ARB RD111 to match.
T8S-456R-NG - Toyota 8' Reverse, Clamshell IFS 4.56 Nitro Ring & Pinion. Fits 3.90 & Up carrier or ARB RD111...