Wheaton 33 low extractable borosilicate glass Precisely constructed with completely interchangeable parts Especially for use in preparation of tissue homogenates, etc. PTFE pestle for soft tissue Grinding chamber clearance is 0.1 - 0.15 mm Unit can be autoclaved These units are designed for use in preparation of tissue homogenates and other similar applications. The PTFE pestle is for soft tissue such as brain or liver. Wheaton 33 low extractable borosilicate glass conforms to USP Type I and ASTM E-438 Type I, Class A requirements. These grinders are precisely constructed with completely interchangeable parts to allow easier cleaning or replacement of damaged mortars. NOTE: although these grinders can be used for power homogenization, jacketed or safety-coated tissue grinders are strongly recommended for user safety.