Hyundai's CCS (Coupe Cabriolet Study) due for unveiling at next week's Frankfurt motor show, is tipped to go into production in 2005 and is the work of Hyundai's Frankfurt-based research and development centre and convertible specialists Karmann. It's based on Hyundai's Coupe 2+2.

The main attraction of the CCS is its unique three-phase slide-and-fold roof - at the touch of a button the driver can switch from a glass roof, to an open roof to a full convertible.

If the weather is changeable, the driver can retract the glass sliding roof back over the rear window (by going over the rear window, headroom is not compromised) - the side supports remain in place so should the weather change, the roof can slide back quickly into position.

Changing to a full convertible just requires the press of a second button which folds in the rear screen, and retracts the roof in a way that still gives maximum luggage space.

The folding roof system is an advance over previous convertible systems as it requires fewer pivot points. Including all the hydraulic and electrical components, the weight increase over the regular Coupe is just 140kg. Hyundai believes solar panels could easily be worked into the structure of the CCS roof design in the future.

While sharing the stylish look of the hardtop Coupe, the CCS features new 18 inch wheels with Michelin 225/40x18 tyres, as well as new front and rear light clusters, which hint at a future facelift of the Coupe.

The interior has also received special treatment, with brown leather Recaro seats, an eight way adjustment and a memory operation. The CCS also has a 280W combination of Becker hardware linked to Infinity speakers.

The usual problem with convertible cars - lack of boot space - is claimed not to apply to the CCS. It has an impressive 443 litres of boot capacity with the roof closed, 244 litres with it folded away.

The CCS has the coupe's 2.7 litre V6 engine and six-speed gearbox.