| RWMA Class | Grade | Description and Primary Uses |
| 14 | 100M | The refactory metal face is RWMA Class 14 (100% molybdenum)(ASTM B387 Type 360) which is typically used for resistance welding or resistance brazing braided or sold copper conductors to ferrous or nonferrous terminals, lugs or fittings. |
| 13 | 100W | The refactory metal face is RWMA Class 13 (100% tungsten) which does not alloy appreciably with non-ferrous materials. Therefore, it is commonly used for cross-wire welding of materials such as copper and brass. |
| 11 | 10W | A refactory metal face is made of RWMA Class 11 (75% tungsten, 25% copper) (ASTM 702 C1D) is brazed onto the base material. This face is typically used for welding at higher pressure and heat common with projection welding. |
