HP's sb21 Digital Projector is clearly pitched at a mobile presenter. It's one of the smallest projectors we've ever seen, weighing in at just 1.2kg and measuring a tiny 14 x 20 x 6cm. The packaging even includes a small setup card explaining how to configure some common notebook models to switch output to the VGA port in order to drive the projector.

The sb21 features a grey, white and silver chassis with a minimalist rear panel offering just a power connector, standard DVI port and proprietary mini connectors for S-Video and composite input. All the connections to the projector are handled via supplied cables, and the unit ships with a VGA/USB to DVI adapter, an S-Video cable and a composite connector. The bundled remote control mirrors the colour scheme and includes a laser pointer for use during presentations, and can even control a slideshow directly, as well as adjusting keystone and zoom options.

The DLP-based unit features a 1000 ANSI lumen brightness rating, matched to an 1800:1 contrast ratio. It has a native resolution of 800 x 600 pixels and can scale 1080i content to fit the screen. In operation, the machine has no problem with brightness, but the tone variations are a little wide for accurate DVD reproduction.

The unit features two telescopic legs (one on the front, and one at the rear), which allows for slight adjustment of image angle, and a tripod mount is included in the base. The tweaking options are relatively limited. However, this shouldn't be a problem during operation as the machine is designed to run off a table in a boardroom, and on the upside, limited adjustments speed setup time. The unit doesn't come with a printed manual; HP instead has opted for a CD-based digital one.

The front, rear and side panels are vented, but the small physical size of the unit limits the fan dimensions, so the internal cooling systems have to work overtime to keep the lamp running at an acceptable temperature. During operation, the sb21 emits a roar that's distracting for watching home movies, but it's fine for a presentation.

The HP sp21 Digital Projector is covered for two years under warranty, which will see the machine through countless demo or presentation sessions, and the diminutive size makes it attractive for anyone in a mobile sales role.