Shaft collar steel.
Grub screw steel or stainless steel A2.

Form A:
Shaft collar steel, bright or galvanised, blue passivated.
Grub screw, steel grade 15H, bright or galvanised, blue passivated.
Form E:
Shaft collar steel, bright or galvanised, blue passivated.
Grub screw steel grade 45H, bright (black) or galvanised, blue passivated.
Grub screw stainless steel A2-70, bright.

Form A: with DIN 553 grub screw (slit)
Form E: with DIN EN ISO 4027 grub screw (hex socket)

According to DIN 705, the stated tolerances apply to blank shaft collars. The tolerances cannot be guaranteed for with galvanised shaft collars. However, this has no influence on the function.

1) Second grub screw from D1 ≥ 75