【Double Waterproofing Security】There are 2 pieces of niches in the package.One stainless shower niche and one Aluminum niche. Aluminum niche works as waterproof box that serves as a protective barrier against water damage, preventing moisture from seeping into the walls. White stainless shower niche 18" with shelf is water-resistant in wet environment like bathrooms. 【Material】Waterproof box is made of Aluminum, which is durability, waterproof. Shower niche white is made of US ASTM standard 304 stainless steel, which could work for a long time. Shower niche surface is well power-coated, which could help protect against scratches and rust for long-lasting durability.100% leak-free and waterproof. 【Size of Aluminum Waterproof Box】Vertical niche.It is flush mounted installation. Firstly, Aluminum niche installed and then stainless niche. Inner size of Aluminum box is 3.86" D ×12.14" W×18.22"H. Seamless welding ensures 100% leak-free and waterproof. 【No Tiled Needed Shower Niche 】Stainless shower niche white 18" is fully finished and ready to mount into your wall opening. Save hundreds of dollars over tiled niches and enjoy the sleek clean look of stainless steel. 92° slope on the bottom of niche can avoid water remaining.With a few simple steps and a minimum material requirement, you ll be done installing on your bathroom wall. 【 Multi-Purpose Storage】Bernkot white stainless shower niches 18" not just for bathroom, also can be used for cupboards, bookshelves, kitchen, etc. It does not take up the building area, more convenient to use. Black shower niche is a clear spot in the interior wall design. It can be used to improve the beautifying environment regardless of family or public environment. 【Easy to install】With a few simple steps and a minimum material requirement, you’ll be done installing this stainless steel shower on your bathroom wall. No complicated processes or necessary tools required. Seal the niche with waterproof sealant. white shower niche with Aluminum Prefabricated Niche