Welwyn / TT Electronics APC Anti-Sulfur Precision Chip Resistors are high-reliability surface mount resistors qualified for use in environments exposed to sulfur-bearing gasses. Welwyn / TT Electronics APC Anti-Sulfur Precision Chip Resistors feature stability, tight tolerances, and precision to ±0.05% and ±10ppm/°C. APC resistors are anti-sulfur tested and qualified to ASTM-B-905-05 and the newer EIA-977 standards, including tests of up to 1000 hours at +105°C and up to 85% relative humidity.