Model Number : 125KHZ TK4100Black,Red ,Green,Gray,Yellow,Blue ,Orange,Purple, Pink, White, Army greenYou can select all one color,for example "please send black". Or mixed color,for example "20pcs blue,30pcs red,30pcs yellow, 20pcs black". If not leave any messages, we will send by random, normally all in blue.Please note, TK4100 read-only and can not write. If you want to buy can rewrite the tags, you should buy EM4305 chip tags.Please open the link to purchase EM4305 chip tags.http://www.aliexpress.com/item/100pcs-Lot-Rfid-Tag-125Khz-Copy-Cards-re-writable-T5557-EM4305-Rfid-Copy-Card-can-copy/1147435209.htmlDescription:Material: ABSDimension: 43.7x30.5x5.3mmResponse frequency: 125 KHz,Chip type: EM4100, TK4100Operation Temperature : -40°C to 85°CWaterproofApplication scope: public transportation, parking, ID identification, attendance system, ticketing, card payment, product logo, etc.Feature:• Water resistant• Each comes with Key ring included. • Compatible with all RFID reader to gain access • Each token pre-programmed with unique ID which is Laser printing on it