Bubble romper.
Romper is worked from the bottom up. First, the Front and Back crotch gusset is worked. Then, the Body is worked in rounds in st st. Next, the Back and the Top front are worked separately. Then, the neckline and leg opening edges are worked.

Yarn: aprox.120 m/50 g.
Recommended yarn: Drops Cotton Merino, Berroco Weekend DK, Gazzal Organic Baby Cotton, Sandnes Garn Duo, Schachenmayr Merino Extrafine Silky Soft 120, Lana Gatto Super Soft, Drops Belle uni color, Naco Bambino Marvel, Adelio Casual, YarnArt Jeans.

Totals used: 100 (150) 150 (200) 200 (250) g (3.5 (5.2) 5.2 (7) 7 (8.8) oz).

Needles: circular needles 3.5 mm (US4) and 4 mm (US6) with cable length 40 cm (16 in).
Notions: crochet hook 3 mm (US2.5), tapestry needle, stitch markers, contrasting color waste yarn, 5 (5) 5 (5) 6 (6) buttons.

Gauge: make a gauge swatch and count your stitches after washing and blocking! It might be necessary to change needle size to achieve a matching gauge. If you knit tighter (have more stitches), use thicker needles, if you knit more loosely (have fewer stitches), use thinner needles.
Approx. 22 sts and 30 rows = 10 x 10 cm in stockinette stitch on 4 mm (US6) needles (after washing and blocking).