Shelf Bra Tank Top, Square Neck Cami with Built In Bra

A bra with a tank knitted over it, not a tank with a pad tucked in
The inside decides how this fits. An elastic band runs under the bust and is knitted into the body rather than tacked at the two sides, and behind the front panel there is an open pocket holding two foam pads. Take the pads out and the tank still stands up on its own. That is the difference between a shelf bra and a cami with a lining stitched behind the chest.

What it does is shape and cover; what it does not do is hold anything down. Walking, pilates, eight hours at a desk, a dinner, all fine. Skipping rope, no. Three things will not work underneath. A strapless bra, because the band leaves nothing for it to grip. An underwire, because the wire lands exactly on the seam under the bust and doubles the pressure at one line. A bonded seamless bra, because the two smooth surfaces slide and it works its way to the waist by lunchtime. A thin long sleeve over the top is the only layer that behaves.

The square is cut, not adjustable
The sliders on the straps change length and nothing else. The front opening is cut square and stays square: near vertical sides dropping from the strap join, a straight bottom edge, corners rounded just enough not to cut in.

There is one consequence worth knowing before ordering. If your shoulders are narrow against your chest, the strap join sits inboard of the shoulder point and the top corner of the square stands off the body instead of lying flat on it. Sizing down pulls the opening tighter across the chest and makes that gap worse; sizing up lets the square sit flatter but loosens the band. Between two sizes, take the larger, wear it under something for the first week, and let the knit relax — the armhole gap closes as the fabric softens, and it will not close if you start one size too small.

It finishes on the hip bone, on a folded hem
The length is why it layers the way it does. The hem lands on the hip bone, below the waistband of most high rise denim, so it stays tucked when you sit down and get up again. It is finished with a folded band roughly a centimetre deep rather than a raw edge, which is what keeps the knit from curling after a few washes.

The same length is why it fails under a tight dress or a fitted skirt. Two layers of knit over a slip read as a ridge, and because the body is close fitting that ridge travels as you move. Over a waistband and under a jacket it disappears completely.

That curve under the bust is holding the front up
Follow the seam under the bust as it curves up towards the armhole. It is not there to draw in a waist. It carries the weight of the front panel onto the ribcage instead of the straps, which is the reason straps this thin do not cut into the shoulder after an hour. A second short seam sits at the side under the arm, where the front panel meets the back.

The price of it is visible on thin fabric: under a fitted white shirt the curve reads as a line across the ribs. Worn on its own, or under anything with some body to it, it is invisible. Worth knowing if the plan is to use it as a base layer under a sheer top.

Five options, and three of them are pairs
The colour list is not five colours. Black and white are one tank each. The other three are pairs: butter yellow with light pink, chocolate brown with baby blue, light pink with desert sage. Light pink appears twice, once beside yellow and once beside sage, so what is on offer is three fixed pairings rather than a free choice of any two.

That is a merchandising question rather than a fit one, but it changes what arrives. If you want two neutrals, or one colour plus a spare of the same colour, none of the three pairings gives it to you — the singles are sold one at a time, and there is one black and one white.