Rock Solid 40 Oz Stainless Steel Vacuum Insulated Tumbler with Copper Plate Technology Keeps Ice Cold for 24 Hours and Piping Hot for 6 Hours No Sweat Performance Ideal for Coffee and Iced Drinks

Single Pack Heavy Duty Double Wall Vacuum Insulated Tumbler
✔️ Rugged steel frame, vacuum walls, forty ounce volume, steady grip

This single unit pack delivers reliable temperature retention for morning coffee, gym workouts, and highway commutes. The vacuum sealed core blocks outside heat while locking your beverage inside, making it a handy choice for desk drawers, gear bags, or car consoles. Condensation stays trapped against the inner liner so your palms and dashboard stay completely dry.

✅ 18/8 grade stainless steel shell resists rust and dents
✅ Copper plated interior lining holds cold heat for hours
✅ Three position slider lid covers spills controls flow rates
✅ Reusable drinking straw pairs with covered sip mode
✅ Textured outer coating prevents handles from slipping
✅ Stands solid on flat surfaces thanks to non slip foundation

💡 Why do double wall vacuum containers outperform single layer metal cups?

Thermal isolation relies on stripping air between parallel steel walls to stop convective heat transfer. This gap physically shields liquid from ambient room temperature shifts. The reflective copper layer bounces infrared energy back toward the center fluid mass. Combining that radiant shield with a friction seal lid kills steam escape paths and maintains consistent drink thermodynamics all day.
- vacuum jackets block conductive airflow through thin metal skins
- shiny metallization reflects radiant heat away from the chamber
- click lock rims arrest vapor diffusion halting rapid cooling cycles