A wearable computer is any digital device that can store and process data and you can carry on your body or clothes. Some practical applications are MediWear, Smart eyeglasses, Smart shoes, Wear Cam, Safety net etc. These are also used in many military applications Plastic optical fibers, Silk organza (computers made up of silk thread and copper) are the examples of material which are used to made wearable conductive cloth. Metallic yarn is obtained from this material which can withstand high temperature. These devices use WOS (wear comp OS) operating system which is compatible with Red hat and GNU Linux. Lead acid batteries were used in earlier versions but now Li-Ion camcorder batteries are also commercially available. Today the cost of implementation is very high but some alternative techniques can be used to implement these at low cost. Considering the various advantages of wearable computers, it can be said that this technology will expand itself into every area of human life.