This is one of the best quality Solder less Bread board. There is no connection problem in this compare to cheap breadboard. This is the original Taiwan made Wish WB-102 Bread Board. Suitable for 20-29 AWG (0.3-0.8mm) wire. This board has groves and edges on both side so it can be used to expand horizontally as well as vertically to form a big solder less bread board for any size prototype. It has slandered 2 distribution strips with 200 contacts and main terminal strip with 630 contacts.