KEYESTUDIO 3D Printer Controller RAMPS 1.4 REPRAP Mendel PRUSA for Arduino Mega It is a Mega Pololu Shield, or RAMPS for short, designed to fit the entire electronics needed for a RepRap in one small package for low cost. RAMPS interfaces an Arduino Mega with the powerful Arduino MEGA platform and has plenty room for expansion. Has provisions for the cartesian robot and extruder. Expandable to control other accessories. 3 mosfets for heater / fan outputs and 3 thermistor circuits.