Direct Info from Product Website : http://www.chihiros.cn/en/productd/m2/id404.html

Chihiros Pipe Spring Brush made of high quality stainless steel spring and high elasticity nylon wire, It is easy to use and the spring can be bent freely to clean all kinds of inlet and outlet hose.

• Flexible and Elasticity design
• Easy to clean inflow / outflow / hose