 Powerchairs have access to the full range of wheelchair options, including ones which are difficult to provide in an unpowered manual chair, but have the disadvantage of significant extra weight.Where an ultra-lightweight manual chair may weigh under 10 kg, the largest outdoor power-chairs may weigh 200 kg or more.Smaller power chairs often have four wheels, with front or rear wheel drive, but large outdoor designs commonly have six wheels, with small wheels at front and rear and somewhat larger powered wheels in the centre.