The Twin Stroke Piston Pumps come under many names:
Wagner, Amspray, Spraytech Apex Series, Krebs, Pro Force
And Titan. There are basically two sizes of pumps, Large and Small.

(Small)

Piston Repair kit #0512228A or #0512221 (Small)
Inlet Valve Kit #0512222 (Small) (Without Push Button)
Inlet Valve Kit #0516292 (Small) (With Push Button)
Wagner 9140, 9140S, 9146, 9150
Amspray 1400, 1500, 1550, 1600, 9150
Spraytech Apex 1420, 1620
Pro Force PF23, PF25
Krebs K2015, K2015S
Titan XT250, XT290

(Large)

Piston Repair Kit #0512229A or #0512178 (Large)
Inlet Valve Kit #0512224 (large) (Without Push Button)
Inlet Valve Kit #0516296 (Large) (With Push Button)
Wagner 9170, 9190, 9210
Amspray 1700, 1900, 2100
Spraytech Apex 1720, 1920, 2120
Pro Force PF30, PF33
Krebs K3017, K4019
Cobra HD9
Titan XT330, XT420

0512224 Large Inlet Valve without push button.

0512222 Small Inlet Valve without push button.

Some of the new units have a push button on the inlet valve. The push and non-push inlet valves are interchangeable.

Inlet Valve with push button.

Piston Repair Kit.

0278227 Prime Spray Valve Assy.

Same day shipping

Part# 0512223 is now 0512178