Super premium flask with a mix of steel and bamboo ? 304 grade steel used inside with natural bamboo outside ? Fully Vacuumized, retains temperature for 12-24 hours! (12 hours hot and 24 hours cold) ? Natural bamboo on the body and lid gives a very elegant look ? Tea strainer allows for both hot and cold detox tea brews ? Rust free, BPA free, leakproof construction ? Capacity: 500 ml (approx) Colours Available: Natural wood