Waterproof transition sleeves, also known as wall penetration sleeves or penetration pipes. Flexible waterproof transition sleeves are generally suitable for structures where pipelines penetrate walls and are subjected to vibration or have stringent waterproofing requirements. After local processing of the sleeve, a primer coat is applied to its outer wall (the primer includes linseed oil or cold bottom oil). Waterproof transition sleeves are divided into rigid and flexible types. The main difference between them is their primary applications; flexible waterproof transition sleeves are mainly used in areas such as civil defense walls and ponds with high requirements, while rigid waterproof transition sleeves are typically used for pipelines in basements and require pipe架 installation.