The 49116-0714 [in hand] is not squared. It is 10 mm externally [socket or wrench], internal hole is a 6mm hex [6 mm metric hex key], and the slot is across the 10mm so you would need a flat blade screwdriver at least 12 mm wide.What @StarTech said.The “slot” is squared, try the business end of a 1/4” ratchet and extension.