Gold sinking process is adopted, lead-free process is used, and the needle arrangement is gold-plated, which is more environmentally friendly25MHZ high speed crystal oscillator & 32.768khz 6PF low speed crystal oscillatorSTM32F411CEU6 support for MicroPython programming with available MicroPython firmware; Support for Ardu&ino programming development; Support C language programming developmentSTM32F411CEU6 there are 3 buttons, reset key, BOOT0 key, user keycolor:Black+yellowMaterial:PCBPackage Contents:3 x STM32F411CEU6 Core Board6 x 20 Pin 2.54mm pitch row Pin3 x 4Pin 2.54mm pitch back bend row needleOnly the above package content, other products are not included.Note: Light 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.