The 813 relief valve has an angle style and a larger outlet size. The ASME certified slope of 1.99 yields, for example, a capacity of 44.0 lbs per minute of air @ 250# set pressure.Features:Traditional Primer Painted CastingLow CostGeneral Purpose813 safety relief valve can be mounted on the following manifolds:#843- ½” x ½” x ½” FNPT (hand wheel)#843F- ½” x ½” x ½” FNPT (seal cap)#846M- ½” x ½” x ½” FNPT (seal cap)#848M¾” x ½” x ½” FNPT (seal cap)