1. Mounting Bushing Material (Indicated by "BPM" vs. "MPM" in the model number): - "BPM" denotes a plastic bushing (typically polycarbonate), while "MPM" denotes a metal bushing (typically nickel-plated brass). - The metal bushing offers higher mechanical strength, greater torque resistance, and improved vibration tolerance, making it suitable for industrial applications involving frequent operation or significant mechanical stress. The plastic bushing is lighter and slightly lower in cost but is more sensitive to installation torque and may be prone to wear under prolonged, high-intensity use. 2. Price Difference: - The MPM version carries a higher price (approximately 4.5% higher), primarily reflecting the material and machining costs of the metal bushing. - The BPM version holds an advantage in cost-sensitive applications. For scenarios demanding long-term mechanical reliability or requiring adaptation to harsh installation conditions, the MPM version offers better overall value. Note: Both models share identical electrical parameters (current/voltage/operational life), protection rating (IP66), terminal type (spring-clamp), and optical characteristics (white LED). No circuit adjustments or panel cutout modifications are required when interchanging them.