They provide:

Superior suction lift capability

Exclusive variable porting options (side, top, bottom and dual)

Thick wall constructed of Sand Casted Aluminum, Cast Iron, Stainless Steel or Alloy C

TPE (thermal plastic elastomers) and PTFE options in diaphragms and check valves

Enhanced with an extended wear package

Weighted ball check valves

Solids range + 1/4" (6mm) to 7/8" (22mm)

Dry primes up to 20 feet of water