The Pro-Ring

Designed in Singapore in the early part of the 21st century, the Pro-Ring has a screw thread closure similar in principle to the Ismail Clamp. It is unclear whether or not it has gone into commercial production.

Sketch, Pro-Ring Photo, Pro-Ring
The Pro-Ring (photograph is believed to show an early prototype)

The following resources were used in the preparation of this web page:
USA flag (316 bytes) Sumobrain logo Singapore Patent 2006/000155.
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