It may look like something oat of Star Wars and the name suggests some pretty advanced technology, out the price gives the game away: this is a first generation image intensifier. There are several Nexgen models, as well as several apparently identical versions sold at inflated prices under the 'Hational Geographic' brand: this 'marine' version is waterproof and is fitted with a 4x magnifying lens. Its distinctive appearance is due to Die infrared source, mounted prominently on top.

More compact than the Night Owl. yet reassuringly chunky, the MVMT 2WP is another 'Gen I' image intensifier from an American company - though, despite the name, it is actually made in Belarus. It's rubber armored and waterproof and is fitted with a 3x magnifying lens. Other models in Yukon's NVMT range include the NVMT 1WP which offers 2x magnification with a correspondingly wider field of view, and is also smaller, tighter - and £10 cheaper.

At first sight, Yukon's Exelon appears to be the same as the NVMT 2WP, but with a bigger objective lens and a very slightly bigger price tag. Like the NVMT 2WP, it has 3x magnification, so one might be forgiven for wondering what the difference is - and why anyone might consider paying more for a product that isn't waterproof and whose lens makes it a bit too big to fit into a jacket pocket. The answer according to the catalogue, is because it has better optics and an improved tube.

Bushnell is better known for binoculars and telescopes, but the company's portfolio also includes a range of night vision equipment, intruding monoculars, binoculars and goggles. In fact, their 'Prowler* appears to be identical to Yukon's NVMT 1WP in everything bar its significantly higher price tag. But the Russian-made Seagull is different - slightly lower magnification than any of the other Gen 1 devices in this group and with the advantage of using easy-to-find AA batteries.

Tne Nightforce Marine 2 is the priciest of the 'first generation' units we looked at in this group, but at least part of the reason for that must be the supplier's address - Knightsbridge. However, there are plenty of e-tailers and retailers 'out in the sticks' somewhere who will happily knock the thick end of £100 off this price.What you get for your money appears to be a Night Owl Explorer Marine with a 3x magnification and a yellow rubberised body instead of flight Owl's blue one.

ATN's website tells us that ATN stands for American Technologies Network and proudly boasts that ATN products were used by US troops in Operation Iraqi Freedom. Hmmm... Personally, I'm not realty convinced that this is that much of a selling point.Fortunately, perhaps, it doesn't really apply to the NVG7, because despite their very military look and feel - and the headmount that came with them - these are 'Second Generation' goggles, rather man current military technology.

ATNs NVM14 is easily the smallest and lightest of the group, but don't let that put you off; it's a serious piece of kit. It shares its stablemate's no nonsense military styling and rugged construction - as well as its 1:1 magnification and sensible use of a single AA battery - and an optional adaptor means you can wear it on your head, all of which makes ft immediately appealing. The snag, however, is that it's offset by yet another hefty step upwards in price, although it's still classed as a 'Gen 2+' device.

The Yukon NVMT Gen 1 monocular, or something indistinguishable from it reappears with yet another badge in the Cobra catalogue, but it's dear that Gen 1 is not really Cobra's core business. Turning over the first page immediately takes you into the realms of Gen 2+ and four-figure price tags. Later pages are full of military-looking kit, with names that sound like fighter aircraft, aimed at the discerning buyer who knows which tube will suit him best from a dozen different choices.

Four different lens options (from 1x to 6x magnification and a gunsight adaptation) and 11 choices of image intensifier tube, add up to over 40 different versions of the all-metal bodied Lightning with prices starting at about £3,000 and rising to double that. At £4,400, this particular version is pretty mid-range with a 1:1 magnification and a European-made Photonis DEP XD-4 Hypergen tube.Power is supplied by 2AM1N1500 1.5V alkaline batteries.