Our proprietary anti-hacking and anti-tracking wireless shielding technology Smooth & durable waterproof nylon Both feature a convenient external non-shielded pocket with patented magnetic closure. Clean embossing and silicone labels. 13" (35*26cm) fits most 13" laptops including MacBook Air, MacBook Pro 13" MacBook Retina 12" 15" (41*29cm) fits most 15" laptops like MacBook Pro 15", Surface Book. Also available in smaller sizes for keyfobs, smartphones and tablets Protect yourself from hacking, tracking, data extraction/wiping. 100% Signal Blocking Faraday Cage Technology shields against RFID, WIFI, Bluetooth, NFC, EMP, Solar Flare, Cellular, GPS