2 different recipes. Brands sell different pigment mixtures under this name, so they won't all look or mix alike. Compare the pigments below.
Who makes it
PB15 Phthalo Blue + PB16 Metal-free Phthalo Blue1
- Schmincke Mussini Resin-Oil No. 10487
PB36 Cobalt Turquoise / Cerulean + PG7 Phthalo Green1
- Lukas 1862 Artists' Oil No. 0119
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.