Waterproof conduit, also known as wall penetration conduit, is generally used in structures subject to vibration or with strict waterproofing requirements when pipes pass through walls. After local processing of the conduit, a primer coat (including linseed oil or cold bottom oil) is applied to its outer wall. Waterproof conduits are divided into rigid waterproof conduits and flexible waterproof conduits. The main difference between them lies in their primary applications; flexible waterproof conduits are mainly used in high-demand areas such as civil air defense walls and reservoirs, while rigid waterproof conduits are typically used in underground pipelines requiring pipe架 installation.