Rubber Cone - 40 x 28mm

Fits Neck: 30-37mm. For use with Buchner funnels and filter flasks, these provide an easier alternative to boring a large hole in a rubber bung. The rubber cone provides a seal between the filter flask and the Buchner Funnel. The seal is not formed at the stem of the funnel, but at the tapered base, when the funnel is lightly pushed down into the cone, which sits in the neck of a filter flask. Choose the rubber cone size which fits part way into your flask neck e.g. a 23mm ID flask neck requires a rubber cone with 19mm bottom dia. & 27mm top dia.

Q = How do these work?
A = When using a Buchner funnel with a rubber cone, the seal is formed between the top of the cone and the tapered part of the underside of the funnel, so it is best to gently push down on the top of the funnel when filtering. The important part is to ensure you have the correct size of rubber cone to fit snugly in the neck of the filter flask. The rubber cone does not need to fit tightly onto the Buchner funnel before using.

Q = Dimensions and neck size fit. 

A = External diameter of large end & Small end = 40 & 28mm.
 Fits neck size 30-37mm diameter.