Batman's Cowl

Dear fellow DC extended universe wiki users, I was wondering, what is Batman's cowl for the standard Batsuit made of? Because in Bruce's knightmare when he is chained up by Superman, who was very easily able to remove the cowl, which makes it look like it's made of rubber, but during the warehouse fight, when Batman is rescuing Martha Kent, one of the men shoots at Batman's head, which fails due to the cowl apparently being bulletproof, which makes it made of something other than rubber. So what do you think Batman's standard Batsuit cowl is made of? Please let me know. Thanks.