The Zero is a mid-range smartphone from Chinese brand UMI. We received ours from Geekbuying.com, which ships to the UK. Also see: Best smartphones 2015 and Best Android phones 2015.

The UMI Zero is the world's thinnest dual-SIM smartphone, and at 6.4mm slimmer than the iPhone 6. Its glass panels, minimal screen bezels and tall body remind us of Sony's Xperia line-up, resulting in a premium look that feels good, too.

The all-metal body is extremely durable, although a Z-shaped case is supplied. Flimsy but light, it's slightly raised at the front to protect the screen.

Unusually you'll find power and volume buttons on the left, while the Zero's headphone jack and charging port, usually top and bottom, are also reversed.

A SIM tray on the right accepts either dual SIMs or a single SIM and a microSD card. It's just a shame the phone doesn't support LTE. Also see: Best budget smartphones 2015 and Best dual-SIM smartphones 2015.

The 5in full-HD Super AMOLED display stands out. Like standard AMOLED, but thinner and more energy-efficient, it produces great contrast but oversaturated colours. Text is sharp, images are clear and video looks great.

UMI's Zero has a 2GHz octa-core chip, with eight Cortex A8s able to run at once. Its general performance is up there with the Snapdragon 800 and Tegra 4 quad-core chips of this world. In our graphics tests it wasn't so hot - in performance anyway; this super-slim phone can get very warm in use.

For photography the Zero has a 13Mp Sony camera with dual-lED flash, while selfie fans will appreciate the 8Mp camera at the front. Also see: Best selfie smartphones 2015.

The Zero is sold rooted, and running Android KitKat. In most respects it's a stock implementation, but you may notice additional ads when closing Google apps such as Gmail.

The high-capacity battery will charge to 51 percent in 14 minutes, or give you 2.5 hours talk time in just five. Note that the charger has a two-pin plug.

Ultra-thin, light, good-looking and tough, the UMI Zero packs some impressive hardware for the price. We award four stars.

Read our full UMI Zero review.