The FR4 (Flame Retardant 4) is a widely used material for Printed Circuit Boards (PCBs). It is a composite of woven fiberglass cloth and epoxy resin, providing excellent mechanical strength, electrical insulation, and resistance to heat and moisture. FR4 is known for its durability, high dielectric properties, and flame-retardant characteristics, making it ideal for a variety of electronic applications, including consumer electronics, telecommunications, and automotive industries. It is one of the most common materials for PCB manufacturing due to its versatility and cost-effectiveness.