CTA - 27mm Low-Profile Metric Cap Socket - CTA-2570 - Black The CTA 27mm Low-Profile Metric Cap Socket, part number CTA-2570, is an essential tool for professional mechanics and fleet maintenance operations. This socket is specifically designed for removing and installing cartridge-type oil and fuel filter housing caps with a 27mm hex nut. Its low-profile design allows access in tight engine compartments, increasing efficiency and reducing downtime.