What is the difference between the H721LC and H-721LC

Forged Brass Construction: High-tensile strength material reduces the risk of cracking under vibration or over-tightening

What should I check if the pilot won't stay lit after installing this part

and AM non-spring return series

Engineered to replace obsolete part numbers RLY1002 and 100167473

MARS 12798 Run Capacitor What is the difference betweenThe MARS 12798 Run Capacitor is a high performance 40 10 MFD 440V dual run capacitor designed for demanding HVACR applications. Engineered for standard round dual run capacitor replacements, this component supports both the compressor (40 microfarads) and the fan motor (10 microfarads) in residential and light commercial condensing units. With a 440VAC rating, it is backwards compatible with 370V systems, providing a robust overhead for voltage