What heating material used in seedling heat mat?

In the market, there are many brands of seedling heat mats, but from the out of appearance, they would all look similar. Do you know what are the materials inside the seedling heat mat?

Generaly there are following 3 types heating materials,

1. Traditional resistance heating wire inside.

2. Flexible PET mat, which is very thin

3. New carbon fiber heating material

The outside of the cover mostly are use PVC. All the 3 heating materials are with good quality, just different manufacturer has different technical, so use different materials. You can buy it on your own demand.