Multi-Radii Test Head£631.00 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 Category: Test Heads Description Description Test Heads include funnels. Related products Test HeadsSingle Radius Test Head £246.00 Add to basket Test HeadsType 304 – CST Test Head £240.00 Add to basket