Apple didn't invent the thin-and-light category, but its MacBook Air now sets the standard for all ultraportables; Intel even encourages other laptop makers to copy the syle under the Ultrabook moniker. There's no exact definition of Ultrabook or ultraportable, but expect to see a svelte laptop with 13in or 11in screen packed in a chassis of 18mm or less thickness. Weight will also be low, at around 1.8kg or less.
Ultraportables almost universally run with solid-state drives, which contributes to their higher retail price as SSDs are still pricey when set against slower but much more capacious hard disks. Some manufacturers are now fitting a new 7mm-high form of hard disk, although these will remove other advantages of flash storage, namely no-noise and shock-resistance.
Processors are universally Intel Core series, often a special low-power version that's recognised by a U suffix. The 1.7GHz Intel Core i5-3317U is a popular and capable part in 2012 ultraportables.
Screen quality is a tempting way for laptop makers to make false economies, as little beyond their size is cited in specification listings. Beware of cheap glossy panels with poor contrast and colour gamut – judge for yourself if possible, taking care to check decent viewing angles, or read through our review reports.
Ports will be more limited due to space issues, but look for built-in ethernet where possible or dongles that allow full-size ports to be connected. Long battey life is always welcome but again due to smaller chassis, smaller batteries will be fitted – and nearly always non-removable. Expect five or six hours of life, although these figures are getting better all the time. And optical drives are all but extinct on this class of computer, but you can always connect an external DVD or even Blu-ray writer by USB.