This is Mega Pololu Shield or RAMPS for short. The 3D Printer Controller Board RAMPS 1.4 is 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 of room for expansion.
RAMPS can only work when connected to its motherboard Mega 2560 and A4988/DRV8825. Owning to its stability in operation and great compatibility with the most 3D printer (all RepRap-model such as Prusa i2 and i3). The combination of Ramps1.4 + MEGA2560 + A4988/DRV8825is becoming a mainstream of DIY 3D printer control board.
The modular design includes the plug in stepper drivers and extruder control electronics on an Arduino MEGA shield for easy service, part replacement, upgrade-ability, and expansion. Additionally, a number of Arduino expansion boards can be added to the system as long as the main RAMPS board is kept to the top of the stack.