BL20 N means number of plates. Length (mm): 310. Width (mm): 76. Thickness (mm): 10+2.3N. Weight (kg): 1.0+0.08N. Channel volume (L): 0.018(N-2). Exchange area (m2): 0.020(N-2). Working pressure: 3.0Mpa. Testing pressure: 4.5Mpa. Working pressure: -160grC ~ 225grC