The STK402-000 series products are audio power amplifier hybrid ICs that consist of optimally- designed discrete component power amplifier circuits that have been miniaturized using SANYO's unique insulated metal substrate technology (IMST).  SANYO has adopted a new low thermal resistance substrate in these products to reduce the package size by about 60% as compared to the earlier SANYO STK407-00 series. ( STK402-020, STK402-030, STK402-040, STK402-050, STK402-070, STK402-090, STK402-100, STK402-120 )