I took one of my freeze plugs out the today and now im gunna put it back in but there is a like a gasket or a teflon type materal on it what is it? where can i get it? i was gunna just use teflon on it but i dont think it will stand up to the head of the motors and i dont know what to use someone please help

 

I used a liquid teflon to reinstall those that I got from the dealership.