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 + PG7 Phthalo Green1
- Grumbacher Pre-Tested Artists' Oil No. P131
PB15 Phthalo Blue1
- Blockx Extra-Fine Oil Colours No. 212550
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.