Limes 8 1 litre flask, five-layer vacuum insulation stated
1 litre · five-layer vacuum insulation stated · 12 h hot and 24 h cold stated · leak-proof with carbonated drinks · scratch-resistant surface
The only flask here that publishes a layer count for its insulation — five — alongside both retention figures, and that never describes the closure holding it all in.
Best for: A litre where the construction claim is what is being bought, and the closure is being taken on trust.
≈ 28 €

