Clamshell Card

What is a clamshell RFID card?

A clamshell card is a thick, rigid RFID card made from two moulded ABS halves sealed around a chip and a wound copper antenna. It is commonly around 1.8 mm thick, more than twice a standard 0.76 mm ISO card, and the extra depth leaves room for a larger low-frequency coil. Most clamshells are 125 kHz proximity cards for door access, time and attendance and parking; the selection rule is simple: match the chip and data format to the reader you already have, and choose the clamshell body when a thick, rigid card matters more than a printed photo.

Clamshell card vs ISO thin card: which one do you need?

Both formats talk to the same 125 kHz reader in the same way. The difference is the body: what it can carry on its face, how rigid it is and how much antenna fits inside.

Choose a clamshell when the card is handled hard, reissued often or hangs on a reel all day, and the face only needs a logo and a number. Choose a thin printed RFID card when every card carries a photo, a name or full-colour artwork, or when you print cards in-house.

Which chip should a 125 kHz clamshell card use?

The body does not decide compatibility; the chip and its data format do. Start from the reader model or a working card from the installed system, then pick the chip that reproduces what the reader expects.

• Proprietary 125 kHz formats: some access systems read a vendor-specific format rather than the EM4100 frame. A T5577 can be configured for several LF formats, but whether a card is accepted depends on the system. Ask your system provider which card format it accepts before ordering, and test a sample on the live reader.
• HITAG and other LF chips: if the reader names HITAG 2, ask for the HITAG 2 card and whether a clamshell body is available for the chip you need.
• Number range: for replacement or expansion cards, send the facility code and number range your system uses so pre-encoded cards continue the sequence.

Can a clamshell card carry a 13.56 MHz chip?

Yes, HF clamshell variants can be made on request, for example with a MIFARE Classic chip for systems that still read one. Availability, construction and lead time depend on the chip and are confirmed in the quotation. For a new 13.56 MHz project, a thin MIFARE DESFire card is usually the stronger starting point, because it can be printed and carries modern cryptography; for sites running both frequencies during a migration, consider a combi card that carries both an LF and an HF chip.

How are clamshell cards numbered and marked?

Numbering links the physical card to the record in your access software, so decide the scheme before production rather than after delivery.

• External sequential number: a running number printed or laser-engraved on the face or back, useful for stock control and issuing.
• Chip ID number: the ID read by the reader, printed on the card in the format your software displays: decimal, hexadecimal, or a facility-code-plus-card-number layout. Send a screenshot or example from your software so the format matches.
• Laser engraving vs printing: engraving resists wear and cannot be rubbed off; ink printing gives more colour choice. Which methods are available for your colour and chip is confirmed with the quotation.
• Logo printing: a one- or two-colour logo on the face is typical; full-colour artwork is possible on some clamshells, but fine photographic detail is better handled by an adhesive label or a thin printed card.
• Number list: a file in Excel, CSV or XML lists every card's chip ID against its printed number, so enrolment can be imported rather than typed if your access-control software has an import function. Pre-encoded clamshells are each verified by a read-back once programmed and shipped with a data report; see the RFID encoding service.

How do you put a photo ID on a clamshell card?

Most desktop card printers are designed for cards close to 0.76 mm, so a 1.8 mm clamshell usually will not feed. The usual approach is to print the photo, name and design on a thin adhesive-backed PVC card or label in your own printer and stick it to the clamshell face. The clamshell keeps the antenna and the rigid body; the label carries the personalisation and can be replaced when a badge is reissued. If every card needs a photo and you issue them in volume, a thin inkjet PVC ID card or printed RFID card removes the labelling step.

Slot punch and attachment options

• Vertical (portrait) slot: the card hangs upright from a strap clip or badge reel; the usual choice for staff badges.
• Horizontal (landscape) slot: the card hangs sideways, for landscape artwork or holders that expect it.
• No slot: for cards kept in a wallet, a vehicle or a card holder.
• Because the slot is moulded clear of the coil, it does not cut through the antenna, which is a common failure point when thin cards are punched after delivery.

Are 125 kHz clamshell cards secure?

A thick, rigid body adds no data security. EM4100-type 125 kHz cards transmit a fixed ID without authentication, so the ID can be read and written onto a rewritable T5577 blank with inexpensive tools. Password protection on an EM4305 or T5577 stops the card from being rewritten; it does not stop the transmitted ID from being copied. For existing LF systems, clamshells are a practical replacement or expansion card. For a new system, or where a copied credential carries real cost, consider an authenticated 13.56 MHz credential such as MIFARE DESFire and plan the reader change with your integrator.

Clamshell card, thin 125 kHz card or proximity fob?

All three can use the same 125 kHz chip, so a site can mix formats on one reader: fobs for residents, clamshells for contractors and printed thin cards for staff. The RFID key fobs for access control guide covers mixed-format deployments; for gate and car-park projects, test the card on the long-range reader you plan to install.

How do you check compatibility before ordering?

• Identify the reader: brand, model and frequency, or send photos of the reader label.
• Send a working card or its ID as your software displays it, so the chip and number format can be matched.
• Confirm whether cards are read-only IDs or must be written by the system.
• State the range you need and test a sample at the real mounting position; read distance depends on the reader and its antenna as much as on the card.
• Check the holder, reel or dispenser against the card thickness and slot position.

Ordering clamshell cards and samples

Send the chip or reader model, slot orientation, numbering scheme and format, logo or printing, colour, whether cards are blank or pre-encoded, the quantity and the destination through the inquiry form. We reply within one business day, and a workable inquiry receives a quotation within one business day. Standard samples are free and a setup fee applies to customised samples; the sample pack lets you test several LF formats on your reader first. Standard products generally ship in 2–3 weeks, and large orders are scheduled individually. Minimum order quantity, unit price and freight are confirmed in the quotation for your specification and destination.

We produce each order in our factory in Shenzhen and draw on established chip supply channels, which keeps project pricing competitive, quality stable and lead times reliable. Quality-system and certification details are on the company page.