The number of petals remaining indicates which types of treatment are still possible :

one petal corresponds to simple cases (S), that is, straight, slightly curved or wide canals.
two petals correspond to moderately complex cases (M), i.e., more curved or narrow canals.
four petals correspond to difficult cases (D), i.e. canals taht are, S-shaped, very narrow, calcified or with extreme curvature.

As a complement to the basic sequence, Instruments to achieve finishes of ISO 40 in diameter.
Pack of 6
Instrument: BT40 40/.04
Lengths: 21, 25, 31 mm
Recommended speed: 800 rpm (600-800)
Torque: 1.5 Ncm
Delivered in a sterile blister. Single use

Ø ISO 50, 70, 90, 110, 130, 150
Length: 15 mm
Recommended speed: 1200 rpm