Protapers of same tip diameter are
PROTAPER INSTRUMERNTS

A unique feature of Pro Taper instructions is each one has changing percentage tapers over the length of the cutting blades.
Pro taper instruments have convex, triangular cross – sections, a changing helical angle and push over their cutting blades and a non-cutting, modified guiding tip.
The Pro Taper system is comprised of three Shaping and three Finishing instruments.
Sx-S1
S1-S2
S2-F1
Sx-S2