Overall Diameter: 56mm. Cutout hole: 48mm. Spring clips will accept upto 4mm wire. Rear terminals are standard 0.25" female spade connector or soldered joints. These good quality terminals are so easy to install - simply cut the holes & push in, secure internally with a small amount of glue. Red and Black bands indicate polarity on binding post, in addition (+) and (-) are clearly marked on the front and the rear.
1 X Round Terminal Cups With Spring Clips For Speaker Builder