Square D A1.75 Thermal Unit Brand: Square D. Part Number: A1.75. Square D Thermal Unit, Melting Alloy, 600 V AC, 1.45 to 1.67 A Full Load, Class 20/Standard Trip, 3.7 in L x 2.6 in W x 1.7 in H Size, Plug-In Mounting, 40 deg C. Additional Description: SQD -A1.75 THERMAL UNIT. Catalog Description: Thermal Unit, Type S, Type A, melting alloy, Class 20..