This is a great item for travel, especially air travel, but there are a couple design issues I'd like to see improved.
The two piece cap tends to unscrew instead of opening because the grab loop is attached to the storage compartment.
I'm not sure if that function is even necessary: the space is entirely too small for any practical use, except storing the cup lid, which is not necessary for me, but possibly some users find useful.
The other major weakness is that the cup section comes apart too easily. This might be partially a result of the lid complication.
I haven't spent enough time with it to see if things get better or worse with time.

This is the 3rd kind of all-in-one bottle we have tried but this design has been the best. Loved how they made the coffee lid as a folded up accessorie inside the water lid.
Only complaint is with the metal material of the water bottle itself. After just a day or so of use, the water takes on a smell and has to be washed out. Not sure if that’s some kind of film over the metal or the metal itself. Doesn’t affect the coffee cup, just the water bottle.

Convenient size for on-the-go, Leak-proof and spill-proof design, Sleek and stylish design, Durable stainless steel material, Great insulation for temperature control, Comfortable to hold and drink from, If you’re into sustainable living, this could be one of the best products for you out there. the tumbler + mug/cup duo is just perfect for your day and also helping nature big time if you buy on the go coffee on a daily.Delivery and service of the seller is also top tier! Couldn’t ask for more, they have exceptional customer service even after sales.I highly recommend that you buy this product.

I have not used the rubber lid for the cup so I cannot review it. I think it’s convenient storage under the cap but a little difficult rolling and stuffing it back in there. I sometimes unscrew that portion of the lid instead of under it. It does keep my cold drinks as such for a good portion of my work day. I am looking forward to see how well it works over summer on hikes. I like the dual colors.