An adapter 14 allows direct connection of a handheld spray device 10 to paint cans 12, 12A, 12B, 12C, of varying dimensions. The adapter 14 includes a cage 60 for holding the paint can 12, 12A, 12B, 12C, a cap 62 that connects the cage 60 to the handheld spray device 10, and a gasket 64 that seals the open upper end of the paint can 12, 12A, 12B, 12C to the cap 62. The adapter 14 may also include a suction tube extension 66 that is connectable between the pump inlet 52 and the suction tube 54 of the spray device 10. A can spacer insert 200 is positionable in the cage 60 to elevate paint cans of varying heights so that the upper ring of the paint can engages the gasket 64.