BoTrays® Disposable Impression Trays are a sturdy. simple. and economical choice when consistent impressions are needed. These disposable green impression trays are made from rigid. high-impact FDA approved styrene and organic FDA approved dye. Alginate “grippers” and slotted walls allow the BoTrays® to provide consistent. unsurpassed impressions with reduced gag effect. No retakes! All materials bond to the tray due to the unique system of holes and slots design which reduces tissue displacement.