I acquired my Snake from John E. Weinel, Inc. in 1986.
My Snake is 376 mm. tall, 80 mm. wide, 9.7 mm. thick, and weighs 443 g. It is made by bending a 3/8" (9.7 mm) stainless steel rod.
There are no markings on my snake.
I am fairly certain that this Snake was made by Tom Martin, who wrote the book Rappelling. Alert readers will note that many of the devices shown in the second edition are from my collection.
The Snake is rugged if, and only if, appropriate metals and diameters are chosen. Many people are scared of snakes because it looks like the rope will just slide off the ends of the bars. This isn't true - the rope actually wraps around the snake, and cannot come off. Wraps can be added or removed to provide incremental changes in friction, but doing so requires lifting the rope over one's head.
Rappelling on a live snake is not recommended.