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. Note: We update our clearance inventory daily; however some items may be sold before they are removed online. We will contact you promptly if an item is no longer in stock. Discount is reflected in product price. 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. Product quantities are limited. Clearance materials are not available for pickup and are excluded from online promo code discounts.