Help identifying Poseidon regulator model...

[rgbmatt]

The service manual (in PDF format) can be downloaded from www.frogkick.dk.

 

[nyresq]

The one thing with the 300 that you have to be aware of s the threads on the hose ports. They are not standard threads. A standard 3/8" or 7/16" hose will start to thread in but a couple turns later will strip out the hole and bung up the reg body, to the point that the port is no longer usable. he thread used is commonly called gas pipe thead. Standard hoses can be used with thread adaptors available from a good scuba supply. The second stage is for the most part, identical to the one being sold today, and most parts for the second are interchangable, easy to replace and are readily available. the first stage parts may be a little harder to come by.
But overall a workhorse reg that for free can't be beat. I'd say get it serviced and use it for a season or two and then sell it on ebay, you see them for sale all the time.

 

[TCDiver1]

it,s definite a cyclon 300,rugged little beast.peace

Interesting, looks a lot like my old Thor.