A bath surround is a complete unit that covers the three sides of a bathtub. Ameribath’s surrounds are made of 100% acrylic, which is a durable, non-porous material that is easy to clean and maintain. Acrylic is also mold and mildew resistant, so your surround will always look new. A bath liner is a partial unit that only covers the front and sides of a bathtub. Ameribath’s liners are also made of 100% acrylic. While a liner does not completely surround your tub, it will still protect your tub from wear and tear and make it easier to clean.