Waterproof sleeve, also known as wall penetration sleeve or pipe penetration tube. Flexible waterproof sleeves are generally suitable for structures subject to vibration or with strict waterproofing requirements during pipe penetration through walls. After partial processing of the sleeve, a primer coat (including camphor oil or cold primer oil) is applied to the outer wall. Waterproof sleeves are divided into rigid and flexible types. The main difference between them lies in their primary applications; flexible waterproof sleeves are mainly used in areas with high requirements like civil air defense walls and swimming pools, while rigid waterproof sleeves are typically used in basements and other pipelines where pipe架ing is necessary.