Job-work procedure: principals can send inputs and capital goods tax-free subject to return periods and deemed-supply rules. Section 143 permits a registered principal to send inputs and capital goods to a job-worker without payment of tax subject to intimation and conditions; inputs must be returned within one year and capital goods (excluding certain items) within three years or may be supplied from the job-worker's premises on tax payment, with the principal responsible for accounts. Failure to return or supply within those periods results in the goods being deemed supplied by the principal on the date they were sent. Waste and scrap may be supplied from the job-worker's premises if registered, otherwise by the principal. 'Input' includes intermediate goods.