The 1986712-4: It uses a screwless push-button clamp termination — push the orange button, insert the stripped wire, release. Side interlocking lets you gang multiple blocks into a multi-position assembly without extra hardware — useful when a design needs more than four circuits on the same pitch.
Wire termination is screwless — push-button clamp style. Accepts 12-30 AWG. The clamp material is steel, contacts are copper alloy with tin plating. Mating orientation is horizontal with the board, so the wire entry is parallel to the PCB — common for edge-mounted terminal blocks in control panels. No screw torque to chase; the push button seats the wire and the spring holds it.