5-Pack Silicone O-Ring Gaskets for Vacuum Flask Lids 4.5 & 5.2cm

Get a Perfect Leak-Free Seal Every Time

Restore your favourite vacuum flask, travel mug, or insulated cup to like-new condition with these high-quality silicone sealing O-rings. Whether your current gasket has stretched, cracked, or simply worn out over time, this 5-pack gives you plenty of replacements to keep every lid sealing perfectly — no leaks, no mess.

Key Features

• Food-Safe Silicone: Made from premium, durable silicone that is BPA-free, phthalate-free, and latex-free — completely safe for use with food and beverages.
• Universal Fit: Designed to fit vacuum flask and insulated cup lids with an outer diameter of 4.5 cm or 5.2 cm — covers the most common sizes on the market.
• Tool-Free Replacement: No tools needed. Simply roll off the worn-out ring and snap the new one into place in seconds.
• 5 Rings per Pack: Stock up and always have a spare on hand for all your flasks and travel mugs.
• Colour: White (as shown in product images).
• Temperature Resistant: Silicone construction handles both hot and cold beverages without deforming or losing its seal.

Product Specifications

Note: Sizes are hand-measured; please allow for minor measurement variation. Actual colour may differ slightly from screen to screen.

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Learn more: Nutrition.gov on cooking and food safety

Frequently Asked Questions

Q: What sizes of vacuum flask lids will these silicone O-ring gaskets fit?

A: These replacement silicone O-ring gaskets are designed to fit vacuum flask and insulated cup lids with an outer lid diameter of 4.5 cm or 5.2 cm. These are two of the most common sizes found on standard travel mugs and thermos flasks. We recommend measuring your existing lid before ordering to confirm compatibility.

Q: Are these gaskets safe to use with hot drinks and food?

A: Yes! The O-rings are made from food-grade silicone that is BPA-free, phthalate-free, and latex-free, making them completely safe for use with both hot and cold beverages and food containers. Silicone is also temperature-resistant, so it won't warp, crack, or degrade with regular use.

Q: How do I replace the old gasket with a new one?

A: Replacing the gasket is very easy and requires no tools at all. Simply roll or peel the old worn O-ring off the lid groove, then stretch and fit the new silicone ring into the same groove. The whole process takes just a few seconds and instantly restores the airtight seal on your flask or travel cup.

Q: How many O-rings are included in one pack?

A: Each pack contains 5 silicone sealing O-rings, so you'll have spares ready for multiple flasks or future replacements when needed.