These terminal blocks are a real cage clamp. The cage opens and closes (clamps) in a linear direction. This design is superior to other cheaper clamps where the screw flexes the tab on the wire when tightened. down the wire. It would be ok if you just insert the wire once and leave it there forever. However, if you're like me and need to move the wires around and reuse the terminal, you'll need a small screwdriver or pickaxe to pry back the tab to open the terminal and make room for the new wire. This applies in particular to stranded wire. The strands do not have the rigidity to push the tongue up and the strands will fuzz and cause a bad connection or short the strands to the adjacent terminals and this is very convenient. oying. Save yourself the headache and use these terminals instead. Sure, they can be a bit more expensive, but they can be used over and over again without the hassle of bent metal tabs from lower quality terminals.