Square D B3.00 Thermal Unit Brand: Square D. Part Number: B3.00. Square D Thermal Unit, Melting Alloy, 600 VAC, 2.11 to 2.3 A Full Load, Class 62/Standard Trip, 4.9 in L x 3.5 in W x 0.8 in H Size, Bolted-On Mounting, 40 deg C. Additional Description: SQD -B3.00 THERMAL UNIT. Catalog Description: Thermal Unit, Type S, Type B, melting alloy, Class 20..