Product Name:  3220 Points Clear Plastic with Color Printed Solderless Breadboard Building and Testing board size(cm): 18.8*18.4*0.85         
plate size(cm): 24*21*0.12   
4 Terminal Strips, Tie-point 2520; 
7 Distribution Strip,Tie-point 700; 
4 Binding Posts; 
Paper Box; 
1pc/ set 

ABS plastic material 
Completely reusable 
Coloured coordinates for easy component placement 
Accepts a variety of wrie sizes(AWG:20-29)

The hole is square. Inside the holes, it is spring clip. It is flexible. It accepts the electronic components which the pin is between AWG 20 and AWG 29. And the inside metal is with good quality. It can bear being inserted many times. 

From the fron side, you can see clearly. First, with the self-adhesive paper, the breadboard sticks on the black plate. Then, use screw to fix strong.