the middle two materials offer quite regular mesh sizes. I like stainless steel mesh better for sieves: Stronger, more precise, easy to weld to a ring and easy to clean.
These nets can probably cause trouble when you sample in sensitive environments since they tend to keep part of the catch in storage and transfer it from pond to pond. I think I will become a millionaire now with a plancton net fixative and deo combination!
My two nets could use it for sure.
@Doron: Thank you for showing your nets - they look very expertly made!
How did you get along with the sewing? I work with lots of materials but am still uncomfortable with cloth and sewing.
The cone angle depends on the free mesh hole surface of the net (and the intended pull ing speed). For a coarse mesh the cone angle can be steeper.
The coarse mesh I ordered will probably be used for the filtration of our inflatable pool in the garden.