Designed for DIY enthusiasts, this PCBA allows you to create your own 18V Li-ion battery pack using 15 pieces of 21700 POWER li-ion batteries. Requires professional knowledge and experience in battery assembly, including the use of spot welding machines, soldering irons, and multimeters. The product is sold as a semi-manufactured good, meaning it does not include battery cells, allowing for customization based on user needs. Actual product size and color from images provided; please you are comfortable with potential differences before purchasing. product, ensuring quality and reliability for your battery assembly projects. This product is ideal for those looking to build their own battery packs for various applications. It is essential to have the necessary tools and expertise to safe and effective assembly. Please note that the product does not come with battery cells, and users must source their own 21700 POWER li-ion batteries. Always follow safety guidelines when working with lithium-ion batteries. Color: As Shown Material: plastic Package Contents: 1* Li-ion Battery Plastic Case PCB Charging Circuit Board 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.