Sks hirschmann 16a pb 4 test sockets 4mm 16a sks hirschmann 973582101 these red 4mm pb 4 tin plated brass test sockets from sks hirschmann are suitable for measuring and testing printed boards the test socket may also be mounted on the printed board using a pan head self tapping screw sks hirschmann 973582101 16a pb 4 test socket mm dc red