Water Tight Air Tight Manhole Cover are designed for preventing water & air from passing through a drainage system or ventilation system. These are used where water ingress or air leakage can cause damage or discomfort. These are made of materials impermeable to water, such as stainless steel, aluminium, or composite materials. Water Tight Air Tight Manhole Cover are designed with interlocking or overlapping edges to form a water-tight seal, preventing water from passing through the drainage system.