The Sea to Summit X-Cup is a 250 ml collapsible cup with silicone sides and a rigid rim, and it folds down to a disc just 1.5 cm high. It weighs 44 g on our scale, has measuring marks on the inside, and it lives in our camp kitchen bag for a quick drink of water or a measure of oats. I paid $13 for it.
What’s in the box
An orange cup made from food-grade, BPA-free silicone with a durable Nylon 66 rim and base. It holds 250 ml, has a measuring scale moulded on the inside, and collapses to 15 mm for packing. It’s the small cup in Sea to Summit’s X range; the X-Mug is a bigger version.
What we like
- Folds to a 1.5 cm disc
- Only 44 g
- Measuring scale inside
- Rigid Nylon 66 rim
- BPA-free silicone
What we don’t
- Small at 250 ml
- Warm to hold with hot drinks
- Folds need a proper wash
Quick Specs
| Spec | Details |
|---|---|
| Brand | Sea to Summit |
| Capacity | 250 ml |
| Material | Food-grade siliconeNylon 66 rim |
| Colour | Orange |
| Weight | 44 g |
| Packed size | 1.5 cm |
Folds almost flat
This is the reason to have one. Push the silicone down and the X-Cup becomes a flat orange disc 1.5 cm high, about the size of a coaster, so it slides into a pocket, the side of a pack or a kitchen drawer bag. Pull the rim up and it pops back into a cup. Next to the Detour collapsible mug, folded, you can see how much thinner it is. On our scale it weighs 44 g folded, a gram under the 45 g on the packaging.
Measuring marks
The inside has a measuring scale moulded into the silicone, so it doubles as a measuring cup for water, oats or rice, which saves packing a jug. The base carries the capacity, the materials and the care symbols. Silicone is easy to rinse, but food can catch in the folds, so give those a proper wash rather than a quick wipe.
At camp
It’s the cup we grab for a drink of water at the car: we fill it straight from the tap of our 8 litre camping water bag and fold it away again. With a hot drink, the silicone sides get warm to hold and they give a little, so hold it by the rim. At 250 ml it’s small for a big coffee, but for water, a short black or a measure, it’s the right size.
Collapsible cups compared
We’ve also tested two bigger Sea to Summit collapsible cups. The Frontier collapsible cup holds 400 ml for 52 g and has a rigid nylon base, and the Detour collapsible mug has a stainless steel inside, so it’s far sturdier with a hot drink and holds 475 ml. The X-Cup is the smallest and lightest, and it folds the flattest.
This one X Cup |  Detour Mug |  Frontier Cup | |
|---|---|---|---|
| Measuring marks | Yes | No | Yes |
| Material | Silicone | Steel and silicone | Silicone |
| Capacity | 250 ml | 475 ml | 400 ml |
| Weight | 44 g | 100 g | 52 g |
| Price paid | $13 | $35 | $20 |
| Our score | 8.7 | 9.5 | 9.0 |
Conclusion: Sea to Summit X-CupConclusion
The Sea to Summit X-Cup is a 250 ml cup that weighs 44 g and folds to a 1.5 cm disc, with a measuring scale inside. It’s the one we grab for a quick drink of water or a measure at camp, and it takes up almost no room. It’s small for a big coffee, the silicone gets warm with a hot drink and the folds need a proper wash. I paid $13, and as a spare cup that disappears into the kit, it’s worth it.
A spare cup that disappears into the kit.
It's the one we grab for a quick drink of water or a measure at camp: 250 ml, 44 g and folded to a 1.5 cm disc. It's small for a big coffee, the silicone gets warm with a hot drink and the folds need a proper wash.
- Hikers
- 4WD tourers
- Campers
Yes, as a spare. I paid $13 for a 44 g cup that folds to 1.5 cm and doubles as a measure. For a big coffee, pick a bigger mug.
