Rockwell Automation, 1492 Centre Jumper for use with 1492-RFB4

The Rockwell Automation centre jumpers use the terminal block wire openings. Multi-pole jumpers can be cut into a smaller number of poles. Jumpers carry 100% of rated terminal block current. The back of IEC style jumpers are insulated with plastic. An adjacent partition plate provides the necessary electrical spacing between adjacent jumpers or between exposed ends of cut jumpers.

They mount without screws into the both spring-clamp terminal blocks and some screw terminal blocks
This is plug-in type centre jumper
This is 8mm 10 pole jumper