Bioquip.com is the best supplier of professional grade entomology tools there is. Everything you could want to collect/examine insects and other small creatures.
As a teacher with a strong interest in science, I’ve owned two of their collapsible pocket butterfly nets for many years. The hoop rims are made of a narrow band of spring steel. When twisted, they result in three smaller loops which are secured with the net bag. A full 12 inch folding net thus fits nicely in my pants pocket while birding in the forest. I just cut a piece of bamboo to make a temporary handle.
— Mike Brady
Available from Bioquip