Why .freeze and .dup SomeGem :: VERSION?

While I was reading https://github.com/thoughtbot/high_voltage source code, I found in the gem spec file:

Gem::Specification.new do |s|
  s.name        = 'high_voltage'
  s.version     = HighVoltage::VERSION.dup

      

        
        
        
      

    

and in the lib/high_voltage/version.rb

file:

module HighVoltage
  VERSION = "2.2.1".freeze
end

      

        
        
        
      

    

What is the advantage of this?