ZK's Industry standard 125 KHz generic prox cards can be used with any of ZK readers which contain an internal prox card reader. Since customers sometimes are already using existing non-ZK card readers and cards, ZK also provides 125 KHz key fobs which can be clipped on to cards having a badge clip slot. For customers having non-ZK cards with no badge clip slot, ZK also offers 125 KHz self-adhesive RFID discs which can be easily adhered