[LCD Calculator DIY Kit]: this DIY calculator kit is the perfect companion for both studying and working. 1602 LCD screen that clearly displays number, the big size of the buttons prevents you from hitting the wrong button, [Easy Assembly]: This soldering practice kit is easy to build and the principle is simple. The connection that was clearly mapped and labeled on the PCB board. Soldering time 2-3 hours, suitable for DIY electronics enthusiasts and can be used as school or family education practice kits. But please NOTE, this soldering kit requires certain foundation of basic electronic theoretical knowledge and welding and hands-on ability. (1) Square root operation. (2) Measure the resistance value of the four-ring or five-ring resistance, enter the color ring colors in order to obtain the resistance value. This feature is designed to help you calculate resistance values without voltmeter. (3) Decimal and hexadecimal conversion to each other. (4) Measure LED current limiting resistance (5) Basic arithmetic operations, with decimal points and negative numbers. (6) Automatic power off without operation within 30 seconds. [Power Supply]: It is powered by two RC2032 batteries(NOT INCLUDED). Due to limited battery capacity, frequent use or prolonged standby may result in low battery power and inability to function properly. Please replace the batteries promptly. Note:It does NOT INCLUDE CR2032 batteries, users need to prepare them!!! Colour:Black Material:Plastic+electronic components Size:Finished product size:12.6x8.6x3.6cm Package Contents: 1 * Calculator Making Kit(Parts) 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.