Each basic unit is built up with a number of elements. The elements are wound with a high grade metallised polypropylene film.

There are various types of metallised polypropylene - MPP - grades.

1. Aluminium metallised polypropylene.
2. Zinc metallised polypropylene.
3. Al-Zn-Al metallised polypropylene
4. Heavy edged metallised film.

The ends are zinc sprayed and output leads are soldered on to the ends. The element assemblies are given adequate outside insulation. They are put in aluminium or M.S. containers. The M.S. containers are surface-treated so as to make them rust free. The containers are put in a vacuum chamber where they are simultaneously heated, dried and degassed so as to reach very high vacuum. While under vacuum they are impregnated with a special grade of capacitor oil, which is bio-degradable and thus constitutes no hazard to environment. Impregnation is done at low temperatures. The impregnated units are taken out, sealed and tested. They are then degreased and painted.

The painting system consists of phosphetising, one primer coat and two coats of enamel paint. Aluminium cans have all the data printed on them.