1. Single NiCr-NiSi WRN-520
2. Double NiCr-NiSi WRN2-520
3. Single NiCr-CuNi WRE-520
4. Double Nickel Chrome-Copper Nickel WRE2-520
5. Single NiCr-NiSi WRN-530
6. Double NiCr-NiSi WRN2-530
7. Single NiCr-CuNi WRE-530 TAG：