FAQ:
1. Question: Can I directly register these tags to my electronic lock?
Answer: No. These tags are blank tags without pre-programmed card numbers. The electronic locks cannot write or program a blank tag. The electronic locks can read only. They read card numbers from programmed tags and then verify it Pass or not.

2. Question: Why can't I copy my old tags/cards to your tags by a card writer?
Answer: First, make sure that your card is the same RFID frequency of 125KHZ. Not all RFID cards are 125KHZ type. For example, another popular key cards use the frequency of 13.56MHZ, which is also called NFC card or IC card. Cards of different frequencies are incompatible. Second, make sure that your RFID card writer can work for the frequency 125KHZ, and that you set it in the right channel. Some RFID card writers have several working frequencies.

ETEKJOY 10 PCS Writable 125kHz RFID Sticker Coin Adhesive Back T5577 Proximity ID Card Token Key Tag Rewritable Dia 25mm

Round-coin-shape sticker, with adhesive back. You can stick it on other stuff (but not metal) if necessary.
Frequency: 125kHz; Chip: ATMEL T5577 (compatible with other universal 125kHz tags); Sensing Distance: 2.5 to 10 cm (1 to 4 inch); Data Storage Life: 10 Years.
Writable & Rewritable. It can be erased and written 100,000 times. Suitable for making new and back-up tags.
Approx Size: 25mm Diameter, 1mm Thickness. Casing Material: White PVC Plastic. Waterproof & Durable.
Package includes 10 PCS.