There are several types of credentials that can be used and/or mixed together for the same system. The most common types are the standard Proximity Cards or Key fobs. These can still be duplicated at most big hardware stores, we recommend SEOS credentials that can’t be duplicated. Biometrics are becoming quite popular and have proven to be very reliable. This technology can come in Fingerprint readers, retina readers, facial recognition, and combinations of both biometric and physical card/keyfob.