What is the difference between the Smart Flow Roller, and the PaintStick EZ Roller?

The SMART Flow Roller has the convenience of being operated in two ways: battery operated or it has a manual trigger that directly feeds paint to the roller cover, eliminating the need for messy paint trays.

The PaintStick EZ-Roller has a trigger that directly feeds paint to the roller cover, eliminating the need for messy paint trays