The ifrothgolf review
A 40oz stainless insulated tumbler with a handle, metal straw, and BruMate's locking "leakproof" flip lid. It's aimed at the all-day-hydration crowd who want a giant cup they can chuck in the car or a bag without it dumping all over the gear.
What's great
The headline trick is real: lock the lid and it genuinely does not leak, even tipped over or rattling around, which most straw tumblers cannot manage. Insulation is the business too, ice surviving well past 24 hours and the outside staying dry with no sweaty ring on the table. Despite the size the tapered base actually drops into a standard car cupholder, and the handle is chunky and comfortable for lugging it round the course or the office.
Worth knowing
It is not flawless. The leakproof seal can backfire: over-tighten the lid and you create a vacuum, so the straw stops drawing until you crack it open, and a misseated gasket is behind a fair few leaking complaints owners post online. Filled with 40oz plus ice it is a genuine lump to carry, the exposed metal straw isn't to everyone's taste (a collapsing version exists if that bugs you), it's hand-wash really, and "leakproof" only applies cold and locked, not with hot drinks. It's also priced well above a basic flask.
The verdict
If you want a proper big-capacity cup that survives a tip-over and keeps ice all day, I rate it, just seat the gasket right and don't crank the lid. If you only need a quick coffee holder, it's far more cup than you need and you're paying for it.
What reviewers say
Buyers love the genuinely leakproof lid and all-day cold retention, and praise the cup-holder fit. The common gripe is the size, the 40oz is large and heavy when full and won't suit every cup holder.
