The extremely efficient DUALL® grinder combines both conical and cylindrical surfaces on a single pestle and tube. These separate areas perform the dual functions of initial grinding in the conical section and final homogenization in the cylindrical section. A PTFE/rubber-lined phenolic screw cap closure permits centrifugation or storage of homogenates without transfer. Replacement components are available and completely interchangeable. Clearance between pestles and tubes is 0.004" to 0.006". Manufactured from 33 expansion, low extractable borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class A requirements.