From Factory Team:
New Factory Team chrome shock shaft options for the smoothest action! They are direct replacements for the RC8T4 and RC8T4e.
Fits: RC8T4, RC8T4e, RC8B4, RC8B4e.
#81609 – FT Chrome Shock Shafts, 3.5 x 35.5mm – $17.85
#81612 – FT Chrome Shock Shafts, 3.5 x 44.5mm – $17.85