6.1.8 Pipet with Filter Unit:
6.1.8.1 A Pipet,, of clear glass with a calibration mark
corresponding to a contained volume of 20 6 0.2 mL at a point
149 6 0.5 mm from the bottom of the pipet (see Fig. 6). It shall
be connected to the filter unit (see 6.1.8.2).
6.1.8.2 A Filter Unit (see Fig. 7), containing the following
elements:
(a) A Brass Body, with a threaded cavity that houses the wire
mesh holder. The cavity shall be fitted with an O-ring of
oil-resistant plastics. The internal diameter of the central tube
shall be 4 6 0.1 mm;