Description/Features: It's designed for maximum compatibility (GRBL 0.9) and versatility with 4-axis support and 6 total end stops for each axis. The expansion board features a PWM Spindle, direction pins, removable stepper drivers, and for micro-stepping setting (driver DRV8825 can do up to 1/32 Mini-stepping). The A4988 stepper motor driver offers a host of features, including low RDS (On) output, automatic current decay mode detection/selection, 3.3 and 5 V compatible logic supply, and five selectable step modes (full, 1/2, 1/4, 1/8, and 1/16). Included is for the R3 board, featuring MCU: , USB interface: CH340, operating voltage: 5V, and equipped with 14 Digital I/O pins (6 with PWM capability) and 6 Analog input pins. The board offers maximum 40mA I-I/O pin output current, 150mA 3.3V output current, and a clock speed of 16 MHz. All of these combined create an unbeatable solution for your 3D printing needs! Specifications: Due to different batches, there may be differences in product appearance and printed text, which will not affect use Material: plastic+metal colour: As Shown Package Contents: 1 x 3D Printer DIY KIT Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.