Bit cap with locking spring for bits of series 1 - 6-sided 1/4" - 6.35 mm
The caps R.235 - J.235 - SJ.235 have a standard locking spring for screw bits that are changed regularly.
Cap R.245 is equipped with a locking spring to hold screw bits firmly in place. For screw bits that are not changed regularly, the square has a hole for ball or pawl locking.