https://uk.frankgreen.com/products/stainless-steel-reusable-cup
This does the job for me
Just make sure you leave the lid off or keep the drinking bit open when storing, otherwise they go smelly and weird.
Thanks for the tip.....I haven't noticed it yet so I must have been doing that
@Nef started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
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https://uk.frankgreen.com/products/stainless-steel-reusable-cup
This does the job for me