Every question, answered.

That's the shape it's built for. A rolled or curved arm gives a narrow object nothing to balance on; the wide flexible base spreads across it instead, and the fins keep the drink from sliding when you shift or reach for the next page. Bump it and it settles back rather than going over.

Yes. Soft, lofted bedding is exactly the terrain the base is built for: it spreads across the loft instead of sinking a point into it, so it holds steady whether you're propped against the headboard or sprawled sideways with the blanket pulled up.

Measure the bottom, not the rim. A base 2 to 3 inches across settles in — the 40 oz Stanley does. Handle-less mugs and camp cups are solidly in range; a handled mug's base usually is too, but the handle lands where a fin needs to grip, so it doesn't seat the same way.

Right on the cushion, no separate shelf or tray required. The base handles the compressing and re-tilting a cushion does under you, which is exactly where the standard add-a-table advice runs out.

No. Nothing clips to a chair arm, tucks under a mattress, or sticks to a sill. It sits on top of whatever you're curled up on and moves with you to the next reading spot in a second.

A cat landing, a blanket shift, a foot tucking under you — that kind of jostle is the whole design brief. The base flexes with the surface and settles the drink back level. It resists tipping, not physics — a deliberate swat or a hard kick still wins — but the ordinary chaos of a lap animal is exactly what it's built to shrug off.

Yes — it holds steady on hard, flat surfaces at least as well as on soft ones. The wide footprint and the grip keep a bumped drink from sliding, which is worth having on a crowded nightstand as much as on a chair arm.

Rinse it or run it through the dishwasher. It's one piece of flexible material with nothing to unscrew or come apart.

It's called the Steadi, molded in small runs in Orange, California by Steadi Labs — veteran-founded and patent pending. Every order ships free from steadilabs.com, with 30 days to change your mind.

Even one-handed reading has hand-offs: swiping pages, thumbing a note, reaching for the light. A Kindle Paperwhite's 6.8-to-7-inch screen is built around a single hand, but that's the hand already busy holding the device — the other one still needs somewhere to put the tea down, and a nightstand or duvet still won't give it a level spot to do that.

It resists tipping by giving the drink a base wide enough to sit on and fins to grip it, but that's not the same as a promise against every knock — a hard, direct hit still wins, and a full glass tipped on purpose will still spill. If you're reading next to a book you especially don't want to risk, keeping the drink toward the center of the cushion rather than right at a fold is still the safer habit.

Those add a rigid, flat surface on top of something soft or curved and ask it to stay level — which is exactly where clip-on trays are reported to slide or lever off a rolled arm, and where folding-leg trays wobble on a mattress. This works the other way: the base itself flexes to match whatever it's set on, chair arm, cushion, or duvet, instead of fighting the shape underneath it. There's also nothing to unfold, clip on, or store when the chapter ends — it moves to the next reading spot in a second.

It doesn't need the nightstand at all. It sits directly on the duvet, the mattress, or a pillow beside you, so a crowded nightstand stops being the only option — and the tea comes off the top of whatever hardcover was serving as the landing zone before.

It solves a problem almost every reader already has and rarely names out loud — where the tea or coffee goes once the book takes both hands. It works with whatever they're already reading on, in bed, in a chair, or on a window seat, and it doesn't ask them to change a single habit to use it.

Either works. It sits on top of whatever you're curled up on rather than attaching to it, so moving one from the armchair to the nightstand to the window seat takes a second. Readers who split their time fairly evenly between a bedroom and a living-room chair often find it simpler to keep one in each spot instead of relocating it daily.

It's one piece of molded material — no fabric pocket to sag or gape the way reviewers describe with caddy pockets, and no clamp hinge or folding leg to work loose the way bed-tray screws reportedly do after repeated use. It stays dishwasher-safe for as long as you own it, which is really just a function of having no separate parts to fail.

The fins flex to seat bases as wide as 3.15 inches, a snug fit right at the edge of what they'll take. A Stanley 30 oz H2.0 FlowState Quencher measures a 3.15-inch base — right at that edge — and an Owala FreeSip 24 oz, at 3.12 inches, seats the same way. The Stanley 40 oz H2.0 FlowState Quencher, at 3.1 inches, has a little more room to spare. Anything past 3.15 inches doesn't seat.

Yes, incidentally — the base sits between the cup and the fabric either way, so a warm tea or coffee resting on it isn't sitting directly against the duvet or cushion the way it would if the cup were set down bare. That's a side effect of the base being there at all, not a separate feature.