Not all walk-in tubs are made of the same material. Some are crafted from acrylic and some are crafted from gelcoat over fiberglass. Acrylic is often said to be less prone to stains and damage, but it’s also more expensive than gelcoat. Gelcoat tubs are usually made with either three or seven layers of a resin coating. A seven-layer gelcoat walk-in tub, which may be called “marine grade” gelcoat, will be more durable than a three-layer gelcoat. The advantage of using gelcoat to make a tub is that it costs less than acrylic and can be molded into a greater variety of shapes than acrylic can be.