✅ EMF HAT >>> Radia Smart EMF blocking hat comes with custom yarn silver fabric. The EMF shielding fabric is effective against radiofrequency RF, 5G, WIFI, Bluetooth. ✅ HIGH EFFICIENCY. Efficiency: Up to 99% Shielding Effectiveness (~50dB). Tested by an FCC- accredited lab. ✅ SIZING >>> The EMF Protection Hat is designed to fit most men and women with adjustable strap. Please NOTE the baseball cap may not be suitable for size XL. The hat circumference is approximately 23”. ✅ PEACE OF MIND >>> We have carefully chosen the best shielding fabric for our customers to use this baseball hat and reduce your concerns on wireless radiation from cell phone, WIFI, laptops, 5G. The EMF shielding fabric covers the complete circumference of the head. ✅ TESTING & CARE >>> To test accurately please use an EMF meter with RF setting (mW/m2). We can guarantee that the shielding fabric works. The hat doesn’t work like a faraday cage that can completely cut off the cell phone signal. This hat however will effectively reduce the RF. Washing instruction: see more information below.