Frequently Asked Question

What is the difference between HID Prox / HID iClass / HID Seos?
Last Updated a year ago

The most important thing to note when looking at the difference between Proximity, iClass, and Seos is the frequency at which they operate. HID Proximity operates at the 125 kHz low frequency while both HID iClass and HID Seos operate at the 13.56 MHz high frequency. HID Seos cards are similar to iClass cards but they are secured a step higher.

125 kHz Low-Frequency Legacy RFID, Prox II, Proximity, ISO Prox & Clamshell Prox:

Low frequency RFID prox cards, tags and adhesive disks are often considered legacy credentials since newer, more secure technologies have come out. Despite the insufficient security of low frequency prox, millions of these credentials are still in use because of their long lasting durability, battery life, and low cost. These qualities make prox cards a popular choice for organizations to purchase as an ongoing consumable to support their physical access control system, even if it was installed more than 20 years ago.

13.56 MHz High-Frequency RFID with HID Contactless Smart Cards, iClass, SEOS:

HID iClass Seos supersedes legacy and existing credential technologies by providing these key benefits:

  • Highly advanced encryption and a software-based infrastructure
  • Unrivaled data and privacy protection that can be used for applications beyond access control
  • Cutting edge capabilities include dual-identity and mobile credentials.
  • Best-in-class cryptography compared to other credential technologies
  • Mobility: Seos is software-based and independent of the underlying hardware chip, providing new levels of form factor flexibility, including use on mobile devices, smart cards, tags, and more.
  • Vertical Applications: Seos can be used to create bespoke solutions across numerous sectors including education, hospitality and government agencies.


Although iClass SE doesn’t offer the same flexibility and security as Seos, iCLASS SE credentials can be considered a more powerful option than standard iCLASS due to a higher data storage capability.

  • It also gets an SIO (Security Identity Object). This makes the card less vulnerable than other 13.56MHz technologies.
  • Can be read from a distance of up to five meters depending on the environment
  • iCLASS SE can be combined with older technologies such as MIFARE Classic.

These additions increase encryption and make the cards more secure, than other legacy options. This is a useful product for larger businesses that require increased security, that may not need all of the capabilities of SEOS.

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