Multi-Radii Test Head£663.00 Multi-radii test head for a Type 319 CST. This test head allows estimation of specific resistance to filtration. Multi-Radii Test Head quantity Add to basket SKU: 31905 Category: Test Heads Description Description Test Heads include funnels. Related products Test HeadsType 304 – CST Test Head £250.00 Add to basket Test Heads319 Single Radius Test Head £258.00 Add to basket