Methods and apparatus are disclosed for using existing envelope feeding machines to print IBIP indicium, and CASS approved address information and bar code information. The current supply amount by the main amplifier is adjusted by a level adjust circuit, according to the difference between the external power supply voltage and the reference voltage. The organic thiol compounds are utilized to plasticize andor heat stabilize halogen-containing polymer compositions especially poly compositions. , separate sliders carrying the read and write elements, relative to the data storage medium with multiple degrees of freedom.