Common denominator

hammerheadfistpunch
HammerheadFistpunch
188
20
Save
Illustration for article titled Common denominator
Illustration for article titled Common denominator
Advertisement
Illustration for article titled Common denominator
Illustration for article titled Common denominator
Advertisement
Illustration for article titled Common denominator
Illustration for article titled Common denominator
Advertisement
Illustration for article titled Common denominator
Illustration for article titled Common denominator
Advertisement

There is a piece of hardware fundamentally common among these vehicles. What is it?