In this start-up kit configuration, you get the Delude Fluid Tool Handle, and the Rocker Frame head, which will accept any 16" - 18" microfiber cover. 

Unique rocking motion allows Rocker to clean with less force and scrub with more force. When mopping the floor in a figure 8 motion walking backwards, the frame rocks back toward you which reduces mopping effort 36% vs. common flat 18" microfiber mop frames.
When you get to a tough spot or scuff mark on the floor, simply push the mop forward, which rocks the frame and delivers 64% more scrubbing force. You don't need to know the physics friction equation to enjoy the benefits of this unique frame!