Wash. Admin. Code § 308-57-140
The following vehicles are exempt from RTA excise taxes imposed in chapter 81.104 RCW:
(2) Vehicles with the following use classes:
C/G (converter gear),
CMB (combination),
CMP (campers),
COM (commercial if powered over 6,000 pounds scale weight or commercial nonpowered),
EX (exempt),
FAR (farm),
FCB (farm combination),
FED (federally owned),
FEX (farm exempt),
F/H (for hire if over 6,000 pounds scale weight and more than six seats),
FIX (fixed load),
H/C (horseless carriage),
H/D (house moving dolly),
LOG (if powered and over 6,000 pounds scale weight),
MOB (mobile home),
PED (moped),
ORV (off road vehicle),
RES (restored),
SCH (private school),
SNO (snowmobile), or
SNX (exempt snowmobile),
STA (stage if over 6,000 pounds scale weight and more than six seats),
TOW (tow trucks),
TRK (if over 6,000 pounds scale weight and 12,000 pounds or less gross weight),
TVL (travel trailer);
[Statutory Authority: RCW 46.01.110. WSR 01-12-099, § 308-57-140, filed 6/6/01, effective 7/7/01; WSR 97-12-015, § 308-57-140, filed 5/28/97, effective 6/28/97. Statutory Authority: RCW 46.01.110 and 43.17.060. WSR 91-04-026, § 308-57-140, filed 1/29/91, effective 3/1/91.]