This cute romper is made using a simple single crochet and a bobble stitch for the front bib and looks super cute with the included rainbow applique.

Materials

dk / weight 3 yarn (I used Drops Cotton Light 50 % Cotton 50 % Polyester 105 Metres per 50 grams)

I also used Emu yarns dk and this worked just as well.

4.5 mm hook

3mm hook and small amounts of rainbow weight 3 yarn

2 x 15-20mm buttons

Preemie 230 metres
Newborn 280 metres
0-3 Months 330 metres
3-6 Months 400 metres
6-12 Months 480 metres
1-2 Years 560 metres

Written in English US terms with abbreviations for UK

The PDF has 28 pages with plenty of pictures and each size written separately.