This is a common design in Germany, as it is sold by a popular entomology supplier. I assume the design can be attributed to Peter Dynort, who worked on Coleoptera and Auchenorrhyncha. Basically, its a ring made from a spring steel strip with a wooden handle, onto which a sheet of fabric is sewn. To fold the beating sheet for travel, the ring can be bent into the shape of an eight and then folded into a smaller double-ring. It will shrink from 72 cm to 27 cm diameter (28 to 10.5 in). It is somewhat stable in folded state, but should be secured with a clamp or kept in a tight container, as it can spring open abruptly and forcefully.

While the foldable design is very comfortable to travel with, I think the design by Lois and Charlie O'Brien is better, as it is sturdier:

When trying to push the circular beating sheet rapidly beneath a low shrub, the spring steel flexes as the ring is pushed in, which alerts the weevils, and they drop before the sheet is in place.