B1/B2, 31/32/Ts, S5/S6-Stainless Steel Series-1250lb

#304 stainless steel
Stainless grease fitting on raceway
Difference between series
RACEWAY
#B1, #31 and TS have stamping formed dual raceways, with 5/8" kingbolt
#S5 is constructed from forged stainless steel, precisely machined single raceway, double welded legs
#5L precisely machined single raceway with grease seal, double welded legs, kingpinless
SURFACE TREATMENT
#B1 is mechanically polished and buffed to a smooth mirror reflective surface, while the majority of other stainless yokes have an electrolyzed shining surface