Anyone remember yellow assent balls???

[JustJeff]

Got them with some used gear when I started diving. Never used them because like several of you havev noted I tend to stay below my bubbles.

I'll post a picture later. Not at home now.

 

[Sam Miller III]

I agree with Walter..they were offered in two colors, however I do believe they were originally marketed for salt water and later for fresh water, the different colors denoted salt or fresh water.

At the DEMA show the manufacture was giving them away. I received a set (or two) used them once or twice and lost them in the kelp beds.

Alex Pierce, a very astute equipment collector in Canada, has a several mint sets of them in his private collection.

All the early magazines, SDM, Dive, Fathom, etc, were filled with products that never made main stream. It is an education in diving history to read these magazines of the 50s & 60s.

sdm

 

[Rob9000]

Yep...
An interesting idea that didn't work very well. Here's one variant (not the ones I've seen, which were just released and followed; just dawned on me that I don't remember them being yellow, but then I don't remember 'em being any other color in particular either - if you'd asked me I'd have probably said white)
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United States Patent # 5308272
A non-mechanical ascent rate indicator for use in saltwater scuba diving. A high density sphere attached by means of a ball chain tether to the gauge, or hose, of a scuba diver has a free rate of ascent of less than 60 feet/minute, the difference in this rate and that of the diver will be shown by the amount to free loop in the tether as it is observed on a horizontal plane even to the diver's eyes. A safe ascent rate will provide a loop of approximately 1 to 11/2 inch.
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Rick

So someone patented having a ball on a chain.