Didnt know you could buy just a truss rod from warmoth. They have several truss rods they use so there isnt one spec. If you want just a truss rod try stewmac.
I bought a truss rod from warmoth for my explorer build. I bought the double action truss rod. It installed easy into my neck. I heard the hot rod truss rods from stewmac are good also.
My gear!
Custom RR style Flying V
Custom ESP Explorer (in the making!)
Vox AD30VT
Dunlop Crybaby, Deltalab Md-1, rd 1, Morley optical Volume