Wheaton® rubber stoppers are manufactured from the highest quality materials to yield exceptional dimensional stability and are available in a variety of styles, sizes, and rubber formulations. Straight plug stoppers provide maximum sealing for vials with straight-wall glass finish. Snap-on style provides maximum sealing for vials with a blow-back glass finish. Sleeve style stoppers feature a fold-over skirt for sealing in serum finish vials without a crimp closure. Autoclavable.