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
PB29 Ultramarine Blue1
- Grumbacher Pre-Tested Artists' Oil No. P160
PB29 Ultramarine Blue + PG7 Phthalo Green1
- Daler-Rowney Georgian (student)Student No. D111014137
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.