Long back caps provide more length and can accommodate longer electrodes than short and medium back caps. They are the most commonly used type of back cap and can be used with new electrodes. Back caps cover the back portion of the electrode on a TIG torch to prevent the tungsten electrode from shorting out during welding. They also put pressure on the collet to keep the electrode in place in the collet and create a seal that prevents shielding gas from leaking out the back of the torch.