The film must suit the product, sealer, tunnel temperature range, and desired finished appearance. Polyolefin, PVC, and polyethylene films can behave differently during sealing and shrinking, so the correct material should be chosen before machine settings are established. Consider film width, gauge, shrink direction, product weight, ventilation requirements, clarity, and whether food contact or other application-specific standards apply. The options within shrink-wrap film can be narrowed according to the packaging task and equipment. Testing the intended film and product together is useful before committing to a large supply order, especially when package shape, sharp edges, or heat sensitivity could affect the finished result.