When it comes to welding accessories, they either fit and work or they don't. If they don't match, you'll lose your shielding gas and either run too fast through your argon tank or your welds will suffer from inadequate shielding. Luckily they fit well with no gas leaks noted. Installing a gas lens allows you to use less shielding gas than with a traditional collet and collet body, but the big benefit for me is that the result is a neat, compact TIG torch. The improved gas flow allows you to use a slightly longer tungsten range, making it easier to see and control the puddle. The only downside to these cheap lens kits is that the lens is made up of brass shields, which lose their effectiveness over time. For the home welder you will still get many days of welding with this kit but you have to keep in mind that the lens is a consumable item and will need to be replaced periodically.