Bertech High Temperature Masking Discs are made of 1 mil thick polyimide film with 1.5 mil thick silicone adhesive. These masking discs are reliable and durable with a unique combination of electrical, thermal, chemical, and mechanical properties that withstand extreme temperatures, vibration, and other demanding environments. High Temperature Masking Discs can withstand temperatures of up to 260 degrees C (500 degrees F). They are packaged on a 3 inch core. RoHS Compliant.