The standard series are: ER-8, ER-11, ER-16, ER-20, ER-25, ER-32, ER-40, and ER-50. The "ER" name came from an existing "E" collet (which were a letter series of names) which Rego-Fix modified and appended "R" for "Rego-Fix". The series number is the opening diameter of the tapered receptacle, in millimetres.

Standards of ER Collets These collets are usually found in a standard series as: ER-8, ER-11, ER-16, ER-20, ER-25, ER-32, ER-40, and ER-50. The numbers represent the opening diameter of the tapered receptacle in millimeters.

ER32 Collets- ER32 Standard Collets Our ER32 collets have a capacity ranging from . 0937 - . 7500 inches or in metric sizes from 3mm up to 20mm. The number shown on the collet is the largest size that particular collet can hold, but it can be tightened to a smaller size.

ER collets have a wide clamping range and high accuracy. While they are designed for tool holding, they work great for work holding in small lathes. With a full set of ER collets you can hold any diameter that is in the clamping range of the set. There are several types of collets that look like ER collets.