Kingtronics FKT-MP series Polyester Film Capacitor: Mylar Film polyethylene terephthalate (PET) Capacitors

 These capacitors are based around the use of a polyester dielectric. As with any capacitor, polyester capacitors have their own characteristics. This means that they are suited to some applications more than others. Mylar capacitors have low levels of moisture absorption.

Mylar is an excellent electrical insulating material, with a high breakdown voltage, very high DC resistance, DC blocking and  Ultra-low ESR.
FKT-MP Mylar Polyester Film Capacitor: https://www.kingtronics.com/pdf/FKT-MP.pdf