I have one. They are handy, but not worth the money. I find them to expensive.
I homemade 10 holders.
If you want i can post some pictures of it. Very easy to made with a broomstick, L shaped aluminium, two bolts and wingnuts. To made it on the broomstick two little woodscrew's.
With out wishing to hijack John's thread. I made a cheap holder from what are called modesty blocks in the UK. They're used in cabinet construction.
Carl.
Gordy, they were designed for watchmakers to hold watches in while working on them, you can pick them up at any Jewellery supplies, but as Marc suggests, there are cheaper versions around
the thing I like about it is you can remove the wooden handle for photographing purpose .
Or in my case, it can stand the oven temperatures when baking thermo clay.
the pins that come around with this object are also handy for indeed closing in rounder objects.
When working on figures always nice to have several homemade tools to attach different parts.