LELK1-1RS4-27129-952 is a single-pole hydraulic magnetic circuit protector manufactured by Airpax/Sensata Technologies, designed for reliable circuit protection and power switching in international applications. This unit features a series auxiliary switch configuration (-1RS4) with 50/60 Hz short-delay trip characteristics (-61), providing accurate circuit control across a wide range of current ratings from 0.02 A to 100 A. The device operates at 65 V DC with an AIC rating of 7500 A per UL 1077 and CSA standards, and 4000 A per VDE specifications, ensuring robust protection against overcurrent conditions. The protector includes standard screw terminals with supplied hardware (10-32 or M5 fasteners with washers and lockwashers) and accommodates panel thicknesses of 0.062 ± 0.005 inches. Common applications include industrial equipment, power distribution systems, and control circuits where reliable overload and short-circuit protection is essential.