HID iCLASS Cards and Fobs: Which iCLASS You Have, What Reads It and Where It Stands

Identify

Which iCLASS do I have?

This page covers HID's iCLASS and iCLASS SE cards, key fobs, stick-on tags and clamshell cards (thick cards with a hard plastic shell). Turn a card over: the lower left corner of the back carries HID's artwork identifier, the HID logo and a model designation, and the word iCLASS there marks a 13.56 MHz iCLASS or iCLASS SE card.

That artwork does not tell iCLASS from iCLASS SE, and it does not apply to key fobs, tags or clamshell cards. HID's markings note says the dynamic marking is needed to identify memory size and to tell iCLASS programming from iCLASS SE (SIO) programming. It is a string of characters printed during factory encoding, and all standard cards, clamshells, tags and key fobs carry one.

A Px mark in the artwork means the card also carries 125 kHz HID, Indala or EM proximity (prox) technology. SR at the right end of the dynamic marking identifies a combined iCLASS Legacy and SIO payload. HID's ordering guide says iCLASS credentials encoded with SIOs were previously marketed as iCLASS SR.

For how 125 kHz prox cards and 13.56 MHz smart cards differ on any brand, see prox cards vs. smart cards.

Source HID's Credential Identification Markings application note, its Readers and Credentials How to Order Guide, and its iCLASS SE card data sheet.

Formats

Which cards, fobs and tags are iCLASS?

HID's product pages list each credential under a number series. The table covers the single-technology cards, the cards with prox added, the key fobs, the tags and the clamshell cards; HID's pages also list cards that pair iCLASS with MIFARE, HITAG or UHF technology.

The key fob, which HID calls the iCLASS Key II, goes on a key ring or lanyard for access control that does not require a photo ID. The tag is a coin-sized disk that attaches to any nonmetallic card or device, and HID's tag data sheet calls it a transition device during the rebadging process. HID does not offer iCLASS SE cards, keys and tags with iCLASS programming.

Memory is given in bits: 2k bit is 256 bytes, 16k bit is 2K bytes and 32k bit is 4K bytes. HID's documents differ on which sizes are offered. The data sheets for the two Key II fobs, the iCLASS SE card and the iCLASS SE + Prox card list 16k bit versions, and the life cycle page lists 16k iCLASS and iCLASS SE cards, keys and tags as General Availability; the May 2026 ordering guide offers only 2k and 32k bit for those credentials.

Source HID's iCLASS and iCLASS SE product pages and data sheets, and its May 2026 Readers and Credentials How to Order Guide.

Readers

What reads an iCLASS card or fob?

HID's ordering guide sorts its credentials by two kinds of reader: standard iCLASS readers, and HID Signo and iCLASS SE readers. It adds that reader support depends on reader model and configuration selected.

On Signo readers the configuration is a credential profile. The Standard, Smart and Custom profiles, and their Priority versions, read iCLASS SE, iCLASS SR and iCLASS; the Seos Profile and Priority Seos Profile do not.

On iCLASS SE readers it is the security keyset. Standard v1 supports credentials with default HID keys, including iCLASS and iCLASS SR; Standard v2 does not include them. Under HID Elite, a keyset unique to one site or company, only that site's Elite credentials work with matching readers.

Reader models, wiring and status are on the HID card readers page.

Source HID's May 2026 Readers and Credentials How to Order Guide, read from the rendered pages for the two tables, and the iCLASS and iCLASS SE card data sheets.

Security

How secure is iCLASS, in HID's words?

HID's product pages describe both iCLASS and iCLASS SE as using mutual authentication, in which card and reader check each other, encrypted data transfer, and 64-bit diversified keys for read/write capabilities.

The original iCLASS pages add: "However, these techniques alone are no longer sufficient to protect card data from modern hacking techniques." HID's PACS Security Guidelines add: "Additional risks exist with legacy credentials using known keys (legacy iCLASS) or credentials with no security at all (prox)."

For iCLASS SE, HID's data sheets list SIO data binding, which they say inhibits data cloning by binding an object to a specific credential, and the expanded iCLASS Elite program for uniquely keyed credentials.

HID recommends that users of legacy credentials upgrade to more modern and higher security credentials like HID Seos. Migration mode is HID's term for a reader configured to accept modern and legacy credentials together; HID recommends a hard cut-off date for it, with legacy support disabled once migration is complete.

For a site with standard iCLASS cards and readers, the ordering guide's recommended path starts with Seos + iCLASS cards and Signo readers in the Smart Profile, and Seos-only cards once every reader on site is Signo.

HID also treats printed card numbers as sensitive information. It recommends ordering credentials without a printed number, or with a non-matching number that differs from the number encoded inside.

Source HID's iCLASS and iCLASS SE product pages, its iCLASS SE data sheets, its PACS Security Guidelines executive brief (linked from security advisory HID-PSA-2024-004), and its How to Order Guide.

Life cycle

Is my iCLASS card still sold?

HID's life cycle page lists each iCLASS part by status. General Availability means available for sale. End of Sales and End of Life both mean no longer available for sale; after End of Life, technical support is available on a commercially reasonable basis only.

The PVC iCLASS + Prox, iCLASS SR + Prox and iCLASS SE + Prox cards, every card listed with a horizontal slot, and the gray-finish tags reached End of Life in 2017 or 2018; the table shows examples. HID ended PICO14443B mode, a communication mode, on all iCLASS credentials on June 30, 2017, and lists PICO15693 mode, the default, as the migration path.

The page says all future dates are subject to change and that its list is not exhaustive.

Source HID's Cards and Credentials Support Life Cycle page, as read on November 10, 2026.

Range and life

How close does it read, and how long does it last?

HID's data sheets give a typical maximum read range for each of several iCLASS reader models, dependent upon installation conditions. The table uses the R40 wall switch reader, where the tag's figure, 1.0 inch, is the shortest for any 13.56 MHz credential in the table.

HID's data sheets describe a passive, no-battery design; the iCLASS card and tag sheets give an estimated minimum 100,000 reads and data retention of 10 years.

Temperature ratings depend on the card body. On iCLASS SE cards, PVC is rated -40 to 122°F and composite -40 to 158°F. HID's iCLASS card data sheet recommends composite cards for printers that fuse images to the card with heat and pressure.

Source HID's data sheets for the iCLASS card, iCLASS Prox card, iCLASS Key II, iCLASS Tag, iCLASS SE card, iCLASS SE + Prox card, iCLASS SE Clamshell and iCLASS SE Key II, and the accessory list in its How to Order Guide.

FAQ

HID iCLASS card and fob questions

Service for HID iCLASS systems in the Bay Area

Elwin Security installs, repairs and supports card reader and key fob systems that use HID iCLASS credentials as part of card reader and key fob access control for commercial and multifamily properties in the San Francisco Bay Area. Calls are answered 8:00 AM-8:00 PM daily at (408) 539-0535.