S555 Triple Proofing Elder Phone, Waterproof Shockproof Dustproof, 2400mAh Battery, 2.2. inch, 21 Keys, LED Flashlight, FM, Quad SIM, with Antenna 1. Four cards and four standby, no need to switch 2. Retractable and detachable antenna to enhance mobile phone signal 3. Phonebook 500, contacts can be grouped, SMS 200 4. 9 groups of family dial: Contacts-options-others-speed dial 5. The earpiece is very loud, which is very suitable for people with poor hearing or sound requirements, noisy people, etc. 6. Multimedia: DV, video playback, recorder, camera, calendar, alarm clock 3 groups, computer, power bank (long press * to turn onoff), 1 game 7. Common shortcut keys: Long press 0 - turn on power saving mode; long press # - mute mode; social software + MP3 + FM shortcut keys 8. The camera can zoom up to 8 times, and the shooting effect can be set 9. Social software: browser, facebook, opera mini, whatsapp 10. Call blacklist, refuse unnecessary interruptions Notice: 1. Change the string command: *#35*#, India, Turkey, Colombia, Azerbaijan need to change to the local string code to use 2. Test command: *#3233*# Test command 3. Countries not allowed to leave: Japan, South Korea, Singapore, etc. 4. The 2G network of AT&T in the United States seems to be closed and cannot be used 5. If the card is not read, it may be that the customer does not use a large card, and the small card cannot be read without aligning with the chip when the small card is inserted. 6. Unlock: upper left +* 7. The phone is unlocked