This Card Works The Same As The Normal Ic Cards, For 1k S50 Standard. Only The Sector 0 Block Zero Which Is Known As The Serial Number/manufacturers Block(chip Cuid) Could Be Programmed To Any Uid You Want. Cuid Card Block 0 (uids Block) Can Be Modified Arbitrarily. Block 0 Directly With Normal Mif Read-write Device Modification. Frequency: 13.56 Mhz Capacity: 1k Bytes Eeprom Memory Rewrite Times: 100,000 Times Read Distance: 0 ~ 10 Cm(depends On The Reader) Initial Key: Ffffffffffff (12f) Common 13.56 Mhz Rfid Reader Writer And Nfc Phone Can Not Write The Particular Cards! Colour:random Color , Dont Accept The Specified Color Material:abs Package Contents: 10 X Cuid Tags Only The Above Package Content, Other Products Are Not Included. Note: Light Reflection And Different Displays May Cause The Color Of The Item In The Picture A Little Different From The Real Thing. The Measurement Allowed Error Is +/- 1-3cm.