Product featuresQuality Material:These prototyping board are made of high quality FR-4 glass fiber PCB thick and sturdy and they do not melt when solder is applied. Top and bottom side are identical copper layersSturdy and Easy to use: All the boards are thick and double sided. The plated holes are tinned and very solid which makes it very easy to solder components4 Sizes Meet you need:  universal printed circuit boards Kit for use in large, medium and small projectProduct DescriptionSpecification:Material: double Side Copper PCB4 different size: 2x8  3x7/ 4x6/ 5x7cmThickness: 1.6mmHole-gap: 2.54 mmHole-diameter: 1 mmMounting hole diameter: 2mmPackage include:5pcs 2x8cm Prototype PCB universal board5pcs 3x7cm Prototype PCB universal board5pcs 4x6cm Prototype PCB universal board5pcs 5x7cm Prototype PCB universal boardWarm Note: After finish a pack of soldering , it's best to put aside for a while to cool down to prevent your fingers from being burned.