Gast K294J service/rebuild/repair kit used on oil-less diaphragm "lab" models with internal filtration (i.e. DOA-P704-AA). Service kit returns your unit to original factory performance specifications. Recommend for service every 2 years. Service kit includes: Leaf valve, Limiters, O-ring, Gasket, Filter/Muffler Elements.
Also recommended for replacement: AF818A.