Super gsm .. Better reception, 4g, wifi faster with possibility of acceleration using the wifi 4g and at the same time awesome fingerprint detection to avoid having to type their code, integrated heart rate monitor ... etc ... That's Awesome all good ... WARNING: some sellers refourguent gsm refurbished !!! Here the seller was Tinbox, the GSM was new ... In Polish but just change the language on first start ... Super happy with the product ... By far the best that I've had GSM (iPhone 4, samsung s4, ....). More faithful color display with respect to the s4 ...