Cube Doors | The Best Modern Waterproof FRP Fiber Bathroom Door Supplier In Kerala. Now Available In Kannur, Kozhikode, Malappuram, Palakkad, Thrissur, Ernakulam, Alappuzha, Kottayam, Pathanamthitta, Kollam and Thiruvananthapuram. What are FRP Doors? From what I know about FRP doors? they are composed of a combination of fiberglass strands and resin, creating a remarkably strong and lightweight material. This composite structure makes FRP doors highly resistant to impact, moisture, warping, and chemicals, making them ideal for both interior and exterior applications.