Stays Warm & Cold Up to 6 Hours: (tested under real conditions). Featuring double-wall vacuum insulation, our insulated coffee tumbler keeps your morning coffee, tea, and other beverages at the perfect drinking temperature all day long Upgraded Leak-Proof Seal Design: This travel coffee mug is equipped with a thickened, food-safe silicone seal and a securely locking lid to fully prevent spills and leaks. No more messy bags, wet clothes, or spilled hot drinks — it's safe to tilt, carry, or toss in your bag without any leakage worries Premium Food-Safe 304 Stainless Steel: Our coffee cups are crafted from safe, BPA-free, rust-resistant 18/8 (304) stainless steel with a smooth, durable matte black finish. No plastic aftertaste, no peeling paint, and no rust, ensuring safe, long-lasting daily use Perfect 12oz Capacity for Daily Commute: Designed with an ideal 12oz size that fits most car cup holders and bike cup holders perfectly, this coffee mug is ideal for driving, office work, travel, and everyday use. It's easy to carry without being too bulky or too small for your coffee and beverage needs User-Friendly Design & Reliable Support: This coffee cup features a smoothly operating lid that opens and closes without jamming, plus a wide mouth for easy hand washing only. If you encounter any issues with your order, please contact us — we will resolve it promptly for you The CS COSDDI 12 oz Insulated Coffee Tumbler is made of premium stainless steel for reliable heat and cold retention. Designed with a spill-proof lid, it’s ideal for daily commuting, office use, gym, and outdoor activities. Its slim profile fits most car cup holders, bike cup holders, and backpack side pockets. Sleek, attractive, lightweight and portable, this travel mug makes a practical and stylish gift for men and women.