Inserts holder double magnet w/depth reg. 1/4"x60

Magnetic bit holder with adjustable depth.
Double magnet: traditional magnet + one ringed shaped which, when in contact with the head of the screw, holds securely even very long screws.
Depth regulator: for a perfect coupling insert + magnet + drive of the screw which makes possibile a considerable tightening pressure and prevents the exit of the insert from the screw head.
Hexagonal shank ¼”