shackle with common tools is more difficult and time consuming than with other shackle materials the lock thus provides a level of security substantially superior to conventional locks application_number US 48297295 A description referring now to the drawings wherein like or primed reference characters refer to identical or corresponding elements and more particularly to fig1 and 2 thereof a padlock is shown having a u shaped shackle 30 and a body 32 the shackle has two spaced parallel legs 26 and 28 and the body 32 has a pair of spaced parallel bores 34 and 36 which receive the legs 26 and 28 of the shackle 30 two notches 42 and 44 adjacent the ends 38 and 40 of the two legs 26 and 28 of the shackle 30 receive a catch for securing the shackle 30 in its locked position in this embodiment the catch is in the form of a locking pin 46 which slides laterally in the body between a locking position shown in fig1 and an unlocking position shown in fig3 two reduced diameter reliefs 48 and 50 in the locking pin 46 spaced apart therealong a distance equal to the distance between the two legs 26 and 28 of the shackle 30 are aligned with the legs 26 and 28 when the locking pin 46 is shifted to its unlocking position shown in fig3 to allow the solid unnotched portions of the shackle leg ends 38 and 40 to pass by the locking pin 46 and be removed from the body 32 to.