Depending on your DOM system, we support Mifare transponder for ENiQ products or 125 kHz transponder for ELS products. DOM Tapkey products do not accept third-party transponder without Tapkey coding. Depending on the administration mode you choose, the third-party transponder have to fulfill some conditions, such as free memory for Data on Card. Also, quality of transponder antenna plays a big role. Therefore, we suggest you to use DOM authorised transponders for DOM devices. Should you want to use third-party transponder for DOM products, we suggest you to contact our service team to check the compatibility of the transponders.