Extraction thimbles, Borosilicate glass Recommended for Soxhlet extraction with solvents, which are incompatible with cellulose fibres and for special biochemical analysis. -Made of 100 % pure borosilicate fibres, without binding elements -High loading capacity and highly permeable to air -Thickness is 1.5 mm (diameter < 33 mm) -High retention of small particles, > 99 % according to BS 4400 -Good stability at high temperatures -Recommended for hot, moist, and acidic gases -Gravimetric determination of particles in hot gases