Brief Guide to IP67 Membrane Switch Circuit Selection For IP67 protection, seal the edge with a 3M waterproof adhesive gasket. Silver circuit – cost?effective, mature process, fast lead time; fits most industrial and consumer products. FPC – higher precision and stronger circuit stability; ideal for performance?critical applications. FPC with carbon coating – adds anti?static protection, electromagnetic shielding, and improved wear resistance in high?contact areas. In short: choose silver for value and speed, FPC for performance, and carbon?on?FPC for extra durability.