Check the listing for details. (10) MERCURY AEROSPACE FASTENERS EXTERNALLY BOLT 557570 5306-00-761-3251. Condition: New. Listed at 50.00 USD. IT IS NO. 10 (0.190 IN.). (5 MM) OR LARGER IN SIZE AND HAS A HEAD WHICH IS NOT DESIGNED TO BE HELD OR DRIVEN WITH AN INSERTED DRIVER OR DESIGNED FOR ROTATION BY THE THUMB AND FINGERS. A LOCKING FEATURE MAY BE INCORPORATED IN THE DESIGN OF THE HEAD OR THREADS.