This service kit will keep your Welch 2052 diaphragm pumps run at top performance. Package includes * Diaphragm x 4 (PN 400732) * 12 x 2 o-ring EPDM x 9 (PN 829217-3) * 25 x 2 o-ring EPDM x 8 (PN 829250-1) * Valve x 8 (PN 400656)