Gas Tank Insulators

[dmclean]

I am installing a new gas tank and one of the insulators has a taper along its length about 14" to 18" long and is a firmer material. Does anyone know which side of the tank it gets installed on? Does it matter? I also can't figure out why.

 

[87GNSteve]

When you say insulators what are you referring to? The rubber material that goes between the tank and the metal strap?