These inexpensive slot head one way security screws are available in BZP (for internal use only) or in A2 Stainless Steel (suitable for internal or external use) ...and are installed using a standard flat bladed screwdriver. 
 
The screw head features a special 'Wing Type' champfer which provides a drive face for the screwdriver to do the screw up, but causes the screwdriver blade to slip off the head during any attempt to undo the screw.
 
Using Power Tools -  if you are intending to use power screwdrivers, etc. for installing the screws, we would recommend the use of our Posidrive Style 'Sentinel' One Way Security Screws rather than the standard Clutch Head screws.
 
NEXT DAY DELIVERY; order your screws before 3pm on a working day and your screws will normally be delivered next working day