Duty-free import of prototype machinery allowed subject to bank guarantee, re-export within prescribed period and sealed transit safeguards. Prototype machinery imported for manufacture, demonstration to secure export orders, or use as capital goods for export production may be imported duty free when defaced or rendered unsaleable. Clearance requires a Bank Guarantee or deposit of duty and an undertaking to re export within the prescribed period; for higher value items an undertaking limiting use to declared demonstration locations is required and customs may seal consignments in transit.