Sell some of the company's second-hand equipment to write what proof of

Sell some of the company's used equipment to write a fixed asset disposal certificate. The company's used equipment belongs to the fixed assets, fixed assets disposal needs more than one department to review, to determine that the equipment has no real value, and then by the purchasing department or the head of the production department, to carry out the work of the asset disposal inquiry, after selling the used equipment, you need to retain the bottom of the equipment purchase and sale contract, the transaction invoices, and the disposal of fixed assets certificate.