The MARS 81138 is a Class RK5 cartridge fuse with rejection-type features

As a genuine Johnson Controls OEM component

Does the spring color-coding follow a universal HVAC standard

and Magic Chef units that specify this part number in their technical literature

Robertshaw 5500-235 Infinite Switch The MARS 81138 is aThe Robertshaw 5500 235 Infinite Switch is a high performance 240V infinite switch designed as a versatile replacement for cooking equipment heating elements. This 5500 M Series commercial grade control provides precise proportionate control of resistive loads, making it essential for electric ranges, hot plates, and warming drawers. Featuring a 5% input at low, this switch ensures granular temperature management across the entire dial rotation. As a