Sea to Summit Delta Insul-Mug



This should be a good product as it ticks all the…

Rating: rated 1.5 of 5 stars
Price Paid: $19.95 NZD

This should be a good product as it ticks all the boxes: It's good size for a decent cuppa (2 cups). It's a stable design that can be put down on uneven ground without tipping over. It's reasonably well insulated and keeps your cuppa hot and your fingers and lips unburnt. It has no unnecessary and therefore redundant handle wasting space in your pack...

However it has one fatal flaw that that's seen it lose its place in my pack. The "leak-proof" sip-through lid has a very poor seal and  leaks worse than any other insulated mug I've ever used - it makes even  the cheapest budget brands seem good by comparison (and it's certainly doesn't retail at a budget price).

Overall it should be a good product but the very poor seal on the lid has let it down and it fails to live up to it's design brief by dripping almost as much of your beverage down your chin as it allows you to drink.


It is a good size mug that keeps my coffee hot. Fits…

Rating: rated 5 of 5 stars
Source: bought it new


It is a good size mug that keeps my coffee hot. Fits well inside my imusa style pot.


  • Design
  • Keeps coffee hot
  • Right size

The slim design allows it easily to fit in my Imusa pot. Not so bulky, holds the right amount of coffee doesn't leak or spill. It's well insulated not hot to the touch and doesn't have a handle which I like.


I bought the cup after being very happy with other…

Rating: rated 3 of 5 stars
Price Paid: About $40 (Hey, Norway IS expensive)

I bought the cup after being very happy with other Delta-products from STS. The cup is stable, big and it holds my beverage warm long enough for me.

I have had no problem with the lid leaking while I drink from it, but as with almost all thermo cups there is no way to make the cup totally "liquid proof". I'd like a cup I can bring into my tent and not have to worry if I accidentally tip it over. Even though I knew this when I bought it, it is now a four star product. 

But the cup, like all cups, needs to be rinsed out/washed, and here is where my second star disappears. The insulation on the cup is just a sleeve, so water/soap will collect under it, and since I didn't realize this I left the cup in a cupboard for a couple of weeks without removing the sleeve to let it dry. The smell of putrid water underneath the sleeve was rather unpleasant the next time I used it.

Even though I have washed it pretty thoroughly it still has a odor to it. Luckily this is only on the outside, so it doesn't give of any taste to my beverages.

I will now use AquaSure or seam sealer to glue the sleeve in place, and make it watertight. Maybe that will take care of this problem?

Update: December 5, 2011

Tried to glue the sleeve in place, but messed it up somehow, so now I have an Insul-Mug with no insulation :) But I have used it all summer because of the weight, and I don't mind drinking lukewarm tea or "hot chocolate".

Found out that the lid needs to be put on immediately after adding the boiling water, or it won't expand to make a seal between itself and the cup. Handling the cup before it had cooled down a bit had to be done by the lip, otherwise I'd burn my fingers now that the insulation sleeve has found its way to a recycling facility somewhere :)