Veroboard PCB. A matrix of punched holes on a 0.1 (2.5mm) pitch. Each donut is separated from its neighbours by  a 0.5mm gap. This ef isolates each pad making it easy to bridge solder across to make interconnections. Each board has `fingers' on opposite ends. The non- solder side of the board has an alpha- numeric grid printed on it to assist in component identification board layout. MEDIUM - 140x95mm, 29x50 holes (1450) 2.5mm edge pitch