Smaller than a phone. Lighter than a thought. The Xteink X3 is the most compact magnetic eReader ever made — a 3.7-inch E Ink device the size of a credit card and the weight of 55 grams that snaps to the back of an iPhone via MagSafe and goes absolutely everywhere a phone goes, without argument, without hesitation, and without adding meaningful weight or bulk to a pocket.
The X3 is a meaningful upgrade from the X4 in the two specifications that matter most for phone-back carry. At 55g versus the X4's 74g, the X3 is 26% lighter — a difference you feel in extended carry. The 3.7-inch display is smaller than the X4's 4.3 inches but sharper: 250 PPI versus 220 PPI — the higher pixel density compensates for the smaller screen size, keeping text clear and comfortable at the reading font sizes most users prefer. For buyers for whom the phone-back magnetic carry is the primary use case, the X3's smaller footprint means a tighter, flatter, more natural-feeling stack on the back of any iPhone.
New hardware in the X3 adds capabilities the X4 doesn't have. NFC enables contactless interaction — tap-to-transfer book files, future app integrations, and digital business card functionality that turns the X3 into a multi-purpose companion device beyond pure reading. The gyroscope enables motion-based interaction including the shake-to-turn-page feature — a genuinely novel interaction for reading, even if most users will prefer the physical buttons day to day. The updated button layout refines the navigation experience based on X4 user feedback.
The 3.7-inch E Ink display at 250 PPI renders text cleanly at comfortable sizes with the paper-like quality that makes extended reading comfortable — no backlight, no blue light, no glare in direct sunlight. Note: the X3 has no built-in front light; use in good ambient light or with the Xteink Magnetic Reading Light accessory. Books load via microSD card, Wi-Fi transfer, or the Xteink iOS/Android app. Supports EPUB, TXT, JPG, and BMP, with 16GB microSD included and expandable to 512GB.
One important note on charging: the X3 charges via a magnetic pogo-pin cable rather than USB-C. The cable is included in the box and functions reliably, but it is not a universal standard — keep the included cable safe. Buyers who prefer the universality of USB-C charging should consider the X4 instead.
Battery life reaches up to 14 days on a single charge at 1–3 hours of reading per day.
The X3 is the right choice for buyers who want the absolute smallest, lightest magnetic eReader that exists — for whom the phone-back carry is the priority and the credit-card footprint is the point. The X4 is the better choice for buyers who want a larger screen, USB-C charging, and a more mature software ecosystem with CrossPoint Reader support.
Box contents: X3 eReader · Magnetic pogo-pin charging cable · MicroSD card · Screen protector · Magnetic ring stickers.