I typically use and prefer 25-millimeter round Near Field Communication (NFC) tags, having found that this size provides reliable readability while keeping the form factor relatively small. Still, it requires a purposeful orientation and momentary hold of the cellphone. I've heard there are some larger form factors that allow faster readability without the exacting placement of the cellphone, presumably because the antennas are larger. Can you confirm this and identify who is manufacturing these larger form factors at this time?
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There are a variety of companies that offer NFC tags, not all specifically in the large-size form factor you're looking for, but potentially with options that would work for you for a longer, reliable read. I'd recommend checking in with the following companies, all of which have fairly substantial product offerings, as well as the ability to work with you on your specific application: Avery Dennison Smartrac, Beontag, Cellotape, HID Global, Identiv, Invengo, STMicroelectronics and SES RFID.
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