Clearance High Impact Polystyrene Sheet Shop for clearance High Impact Polystyrene overstock, remnants and drops. High Impact Polystyrene (HIS) is a low cost, tough plastic that is easy to thermoform and fabricate. HIS is often used for countertop point of purchase displays and indoor signs. Please note: Discount is reflected in product price, and clearance quantities are limited. While we update our clearance inventory daily, in rare instances our website may not reflect a very recent sale. We will contact you promptly if an item you ordered is no longer in stock. Can’t find what you need? Shop all HIS Materials or Get a Quote. We cut everything! Select your item, give us your cut requirements, we'll do the rest. Compare products selected. Clear List Prev Page - Next Compare products selected. Clear List Prev Page - Next Prices and product availability are subject to change without notice. Clearance materials are not available for pickup, are excluded from online promo code discounts, and are not returnable.