SPIF TRAILER DESCRIPTION PIPING DIAGRAM NO SPIF 4S/3M ABS 6-Axle (2+3+1) Semi Trailer P-7851 SPIF 4S/3M 5-Axle (1+1+3) Trailer P-8122 SPIF 4S/2M 4-Axle (1+3) Semi Trailer P-8136