Convenience: The smaller/front pocket is anti-radiation, best for storing ID card, bank cards, etc; The larger/back pocket is for signal blocking, best for storing car key fobs. Easy to Carry: Available in sizes 3.25″ x 4.75″ (S), 3.5″ x 5.0″(M), and 7.75″ x 4.25″(L); Secure closable flap with elastic accommodates multiple sizes of keychains and small devices; The integrated keychain hole provides more flexibility.