Description: 1. PCB Heatbed MK2B Relative latest version Mk2a, a major upgrade to the 12V 24V dual power. 12V connection: a cable connected 1, 2 and 3 in addition a line connected simultaneously 24V Connection: a line then 2, then 3 in addition a line (not connected 1 vacant) Read more here:http://reprap.org/wiki/PCB_Heatbed Specification: Color: Red Size: 214mm x 214mm Etching: 35um copper Laminate: FR4 1.6mm 2. 3D Printer Controller RAMPS 1.4 The RepRap Arduino-compatible MEGA Pololu Shield, or RAMPS for short. It is designed to fit the entire electronics needed for a RepRap in one small package for low cost. RAMPS interfaces an Arduino-compatible Mega with the powerful Arduino-compatible MEGA platform and has plenty room for expansion. The modular design includes plug in stepper drivers and extruder control electronics on an Arduino-compatible 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. 3. Arduino-Compatible Mega 2560 R3 Fully compatible with original Arduino MEGA 2560 R3, with this product, you are able to use all the Arduino open source platform to create or learn interactive objects, it will be a lot of fun while you are creating and learning it, so just get this and start it, we also provide reference pdf files that can help you to improve skills very quickly. after all, time matters, the sooner you can improve your programing skills, the sooner you can create amazing projects. Compared with UNO R3, this is with main Chip ATmega2560, with more I/O Pins, and additional 10 PWM output, of course, the EEPROM is also with larger space. 4.The DRV8825 stepper motor drive carrier plate TI DRV8825 micro bipolarbstepper motor drive is a breakthrough. The module has a pinout and interface with our A4988 stepper motor driver carrier is almost the same, so that it can be used as a more high-performance drop-down menu of these boards alternative