Which tool for this connector

[feebs]

Needing to add another cable to one of these, so before I jump in & break something, is there a special tool to open this or do I just use a screwdriver? I don't wish to remove it - just open one side.

Thanks in advance

[wingless]

Looks like a large flat blade screwdriver is used on the rotating clamp.

[capngeo]

Damnit! Just when I thought I had all the gizmos in the World, someone always comes up with something cool........ where'd you get that?