4M-005 FULL ASSEMBLY FOR HORIZONTAL RECIPROCATING MOTION INCLUDING: Horizontal Slide Drive Mechanism  Slide Crank Link DC Motor Belt Gears/Drives/Mechanicals Optical Sensors and Code Wheels Housing All Hardware Fits Following Models (pick from dropdown at checkout): mamaRoo 1.0 (4M-005) manufactured 2010 through 2012 mamaRoo 2.0 (4M-005) manufactured 2012 through 2015