Model MK8A is a special freeze-protected valve that drains
water from Model 8300FP combination shower/eyewash after
closing to prevent freezing. 3/4" NPT inlet. Standard sizes are
60" and 78" (152.4 and 198.1 cm) for bury depths of 24" and
42" (61 and 106.7 cm) respectively. Servicing Instructions: For
replacement of damaged parts, order the VRKMK8A repair kit
which includes packing, stuffing box, stuffing box nut, spring
and plunger assembly with four O-rings.