Quick answer
To keep your Kelso tumbler leak-proof in a lunch bag, always check the silicone spout valve is clean and fully closed, then pack the tumbler upright with the lid securely twisted on.
Why leaks happen with kids' tumblers
Even a well-designed tumbler can leak if the lid isn't seated correctly or the spout valve is blocked by food debris. The Kelso tumbler's silicone sipper spout has a built-in valve that stops water flow when no one is drinking, but crumbs or dried milk can prevent it from sealing fully.
Lunch bags often shift during transport, so a tumbler that's packed on its side or upside down is more likely to leak, especially if the lid isn't tight.
Steps to keep your Kelso tumbler leak-proof in a lunch bag
- Check the lid seal and spout valve: Before filling, inspect the silicone spout valve for cracks or debris. Rinse it under warm water if needed. Make sure the spout is in the closed position (no air hole exposed). A dirty or damaged valve is the most common cause of leaks—clean it after every use.
- Twist the lid on until it clicks: Place the lid on the tumbler and turn it clockwise until you feel a firm stop. The lid should sit flush with the rim—if it wobbles, remove and realign the threads. A loose lid can let liquid seep out even if the spout is closed.
- Pack the tumbler upright in the lunch bag: Place the Kelso tumbler in the main compartment with the bottom flat against the bag floor. Avoid laying it on its side or stacking heavy items on top that could press the spout open. Packing upright reduces pressure on the spout valve and prevents accidental opening.
Product facts
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Kelso Tumbler, 15 oz. (2 Pack): The silicone sipper spout has a built-in valve that stops water from flowing when no one is drinking. This valve is your first line of defense against leaks, but it only works if it's clean and the spout is fully closed.
Kelso Tumbler, 15 oz. (2 Pack)
