Internal drive heads of small diameter are very problematic, particularly when rusty or gouged. But a well-chosen screwdriver or impact driver can get you out of trouble.
Makita GWT07D 40V Max XGT Brushless Lithium-Ion Cordless 4-Speed Mid-Torque 1/2 in. Sq. Drive Impact Wrench Kit with Friction Ring Anvil and 2 Batteries (2.5Ah)
