Features: The size is 7x9cm, for small circuit design, and convenient for various experiments and prototypes production. The thickness of board is 1.6mm, providing good mechanical strength and durability, suitable for long use. The hole spacing 2.54mm (100mil), which meets international standards and for multiple standard components, making it easy to weld and connect. Both side of board have undergone tin sprays, which improves the welding performances, enhanceds the reliability of electrical connection, and ensures a smoother welding process. Using FR4 fiberglass materials, it has good insulation and heat resistance, and can maintain stability during high temperatures welding processes. Specifications: Materials: Plastic + Metal Size: 7x9cm/2.76x3.54inch Package Includes: 10Pcs sprays Tin Board note: Please allow 0-1cm error due to manual measurement. make sure you not mind before bid. Due to the differences between different monitors, the Pictures may not reflect the actual of the item.