The task comes first.
Recognize the tool by what you need it to do. Check the stated size and included items before choosing.
Vacuum filtration.
A Buchner funnel has a cylindrical cup with a perforated plate. The two-part construction separates from its lower section. A side-arm flask, suitable adapter and vacuum connection belong to the surrounding setup, not to the funnel listing.
For the 13cm Eisco Labs listings, the stated filter-paper range is 11–12.5cm. Do not transfer that fit range to a different funnel size.
All Buchner funnels
Pour-transfer work.
A long, narrow outlet leads liquid into a narrow-mouth receiving container. The filter-funnel range lists five diameters. The four-piece Eisco Labs set instead includes four different sizes in one purchase.
All liquid-transfer funnels
Solid-material transfer.
The powder-funnel family has a short, broad outlet. The parallel-stem listing describes solid-material transfer; compare its actual diameter options with your intended vessel and task.
All powder funnels
Liquid-liquid separation.
The separating range combines a polypropylene body, PTFE-plug stopcock and screw cap. Compare the listed capacities rather than choosing by photograph scale.
Racks, receiving vessels and other laboratory apparatus are not included.
All separating funnels
Bulk transfers.
A larger mouth and top-mounted handle distinguish the industrial funnel. Choose between the actual 20cm and 25cm listings; size alone does not establish a fit with every container.
