Soft TPR Bristles,protect the surface of the cup and bottle from being scratched,flexible enough to slip through narrow areas to reach every nook & cranny but always keep their shape, and will not break off or fall apart. Quality material, easy to clean glass, ceramic cup, plastic cup, vacuum flask, no residue, more environmentally friendly and safe. Long handle,special for cleaning the small entrance and deep bottle. Ergonomic handle for added fit and comfort. Safty quality enough to FDA test,dishwasher safe and heat-resistant up to 450°F (230°C).