And unlike the first PadFone, there's still no docking keyboard with a built-in battery, so you can't use the Infinity like a laptop. In principle, the hardware here is more similar to the PadFone 2 than the original PadFone: the phone docks vertically into an exposed bay on the back of a 10.1-inch tablet module aka the PadFone Station. Plus, there's always the handy, but less elegant USB OTG for storage expansion via flash drives.
But as with the PadFone 2, ASUS offers 50GB of cloud storage, free for two years. What you won't find on the Infinity is a slot for microSD expansion, so you'll have to choose carefully between the 32GB and 64GB models.
Finally, sandwiching the micro-USB port are two round sockets for the tablet module's external antenna, catering to cellular signal (worldwide model: WCDMA 900 / 2100 with DC-HSPA+, and LTE 800 / 1800 / 2100 / 2600) as well as Bluetooth 4.0 and 802.11a/ac/b/g/n. It also provides a snug fit with any ordinary micro-USB plug - something that the PadFone 2 failed at. Unlike the PadFone 2, which had a 13-pin MHL connector, the Infinity's micro-USB port integrates the MyDP (Mobility DisplayPort) interface for twice the performance of MHL (at 5.4Gbps, which allows 1080p60 playback). The top edge is occupied only by a 3.5mm headphone jack, whereas the bottom side houses the microphone and a micro-USB socket. The top and bottom sides actually consist of well-disguised polycarbonate, which enables better reception through what's otherwise an all-metal body. On the other side of the phone you'll only find a pin-ejection tray for a nano-SIM card, which makes the Infinity the first non-Apple device to adopt the new standard (the fake iDevices don't deserve recognition here, obviously). Interestingly, the loudspeaker's now located on the right side just above the power button and volume rocker, so it's less likely to be blocked in various scenarios. The phone's four sides feature a matte finish in the same color as the back - either "titanium gray," "hot pink" or "champagne gold" (color availability may vary across regions). As for the front, the protruding, scratch-resistant Corning screen lens covers almost the entire surface, leaving a shiny 1mm-wide chamfer from each side of the metallic body to reduce the chance of shattering when dropped. The back side alone easily makes this one of the best-looking devices ASUS has ever created.
Near the top you'll find the usual camera and its LED light, then at the bottom there's the "PadFone" logo above a T-shaped NFC antenna band - a feature seen on some metallic phones like the Xperia Ion, Xperia P and the HTC One. How clean? The back is dominated by the straight brushed-metal pattern, though there are a few features garnishing it as well. However, these are trade-offs that we're willing to accept for the sake of the Infinity's versatility, solid feel and clean look. It would have also helped if the screen bezels were less than 4mm thick, thus keeping the phone narrower. The two previous PadFones, on the other hand, had well-rounded corners that fit our hands better. While the back's gentle curve does make for a somewhat comfortable grip, it stops dead at the straight sides and therefore produces relatively sharp edges. Instead of the signature Zen-ripple etching on the old polycarbonate cover, the almost fully metallic Infinity features a vertical brush pattern across its back - one that is ever so slightly curved when viewed from either the top or bottom, making the thickness vary from 8.9mm in the middle to about 6mm at the edges. The Infinity utilizes a brand-new design that takes advantage of an aerospace-grade, twice-anodized aluminum alloy construction. On the other side of the phone, the old 1.2-megapixel front-facing camera has been replaced by a 2-megapixel, f/2.0 module (it's an OmniVision OV2722 sensor, if you care), but the backlit capacitive soft keys below the screen are here to stay.
The main camera uses the same Sony 13-megapixel IMX091 sensor as the PadFone 2, but its lens has been upgraded from f/2.4 to a brighter f/2.0. Unsurprisingly, the Infinity comes with a bigger built-in battery - 2,400mAh, which is a nice bump from the old 2,140mAh cell.
In terms of resolution, viewing angle and color gamut, the newer screen is a significant upgrade from the predecessor's 4.7-inch, 720p panel though the screens from both generations belong to Sharp's LTPS line (not to be confused with the newer IGZO line, which is currently less efficient at this panel size).
Like many of the latest Android flagships, the PadFone Infinity comes with a 5-inch, 1080p display and a quad-core chip.