ER nuts are basic nuts with surface treatment for friction reduction. They have slots on the outside diameter and use a spanner wrench for nut tightening.
C Collets are reduction sleeves for clamping smaller diameter cylindrical tool shanks. Used in Hi-Power Milling Chucks and MEGA Double Power Milling Chucks.
The Lollipop cutter from SPHINX is the newest addition to its end mill cutter lineup. It is ideal for machining undercuts, deburring and multi-axis machining.