Duty-free removal of excisable goods allows manufacturers to send semi-finished goods for testing subject to prescribed conditions. The Commissioner of Central Excise may, by special order and subject to specified conditions, permit a manufacturer to remove excisable goods that are semi-finished for further manufacturing processes or to remove excisable goods for testing to other premises and bring them back duty-free, or transfer them to registered premises for removal on payment of duty or without payment for export; the testing provision excludes goods described as 'prototypes' sent out for trial or development tests.