I can conveniently insert my credit card into the 'SC' slot on my HP

What is the SC card slot all about? hp elitebook sc slot Predám notebook HP EliteBook 840 G5 s výkonným CPU Intel Core i7-8650u procesor Intel Core i7-8650U 2GHz, RAM: DDR4 8GB + voľný slot hpe 800w flex slot platinum hot plug low halogen power supply kit So I'm shopping around and I land at a HP laptop An HP Elitebook 1040 G3 The seller on ebay doesn't even mention anything about the SC slot

hpe 1600w flex slot platinum hot plug low halogen power supply kit Shop India for HP Victus cm Gaming Laptop 16-s0095AX, Blue Includes AMD Ryzen™ 7 processor and NVIDIA® GeForce RTX™ 3050