... .Anti-theft devices Master and supplementary card can work in pair,one to one or one to many and ... one to eight)2.Master card will be used by main user,supple metary card will be used on ... effective rang can be customized, to protect the object with in the covered area, can be adjusted from 1-50 ... is the best gift and can be used widely in bank, telecom, insurance, stock exchange, education and home ...