The Victor Technologies Tweco Classic Number 4 MIG gun, an enhancement of the Number 4, includes higher impact resistant materials, an interlocking handle design for superior toughness, an angled trigger for a more comfortable pull and refined, modernized lines. Its handle is flatter making it easy to handle and its heavy construction offers durability, according to the company. The MIG gun has a rating of 400 amps at a 60 percent duty cycle.