These grinders are precisely constructed with completely interchangeable parts to allow easier cleaning or replacement of damaged mortars. They are designed for use in preparation of tissue homogenates, and other similar applications. The Teflon® pestle is for soft tissue such as brain or liver. The stainless steel rod is 0.25 inch (6.3 mm) in diameter. The grinding chamber clearance is .004 to .006 inch (0.1 to 0.15 mm). This unit is autoclavable and can be used for power homogenization as with our overhead stirrer. However, the use of a safety-coated tissue grinder for added safety is strongly recommended. This unit is manufactured from Wheaton® 33 low extractable borosilicate glass (meets ASTM Type I Class A and USP Type I standards).