siless liner 314 mil 18 sqft sound deadening mat - sound deadener mat - car sound dampening material - sound dampener - sound deadening material sound insulation - car sound deadening siless siless liner is a high density, closed cell foam that serves as an efficient heat and sound absorber. closed-cell foam is an effective material for reducing noise reverberations, and the siless liner is moisture-resistant, fire-retardant, and dust-free. our heat-blocking foam rolls are pliable and easy to work with, and they install in minutes. the high-density closed-cell foam is perfect for firewall, doors, roof, trunk and floor. siless liner is the most effective automotive thermal insulator available online, and perfect to use on top of siless sound deadening mat. it is a soft, self-adhesive closed cell foam with many thousands of cells packed extremely close together, which gives the material near zero air infiltration. this is the key to its ability to reduce heat, as well as resist oil and water. since it will not hold water, it will not promote rust like most under carpet padding and thermal insulators. siless liner is also durable enough to be crush and tear resistant. because of its durability and ability to resist oil and water, siless liner is long lasting. siless liner has the highest heat blocking properties available in a single layer synthetic foam. combined with siless sound deadening mat, its nearly doubles the total thermal resistance ability. it provides excellent insulation for the roof, firewall, floor, quarter panels, doors, and even under the hood.