This is a vintage SeaPro Zepher 2nd stage regulator which is an apparently very uncommon or just not talked about on the internet. It has a very unique design with a side vent and and angled hose attachment. The white nob looking thing stops free-flow by pulling it out. If it looks like the hose attachment point gets in the way let me assure you that it does not. All of the internal rubber components are in fantastic condition and the regulator appears to be in working order. I will test it if someone wants me to. I strongly suggest that you read the article in the pictures for more information on it. This would make a great addition to a regulator collection. I will sell it to anyone who offers a reasonable price or a working more modern 2nd stage regulator or any other reasonable offers. I am completely open to negotiation.