PPG Aerospace PR1776 MB2-B1001 Light Fuel Sealant Semkit 654 BMS 5-45 - 100 mlPR 1776M Class B is a low density, high temperature aircraft integral fuel tank sealant. It has a service temperature range from 65F (54C) to 250F (121C), with very limited excursions up to 360F (182C). This material is designed for fillet sealing of fuel tanks and other prolonged exposure to aircraft fuels both jet fuel and aviation gas, and will resist limited contact to diphosphate ester based hydraulic fluids.