This is a new invention I created, it is being manufactuered by H2Odyssey and will be available some time in September for around $130 at the store. Here is Underwater footage of two Scuba Divers shooting each other with Bubble Rings. The device is a Torid Pulse, it is a sort of Bubble Gun that attaches to the low pressure port of your scuba tank, just like a back up regulator. It will shoot round Bubble Rings up to about 35'.

The device is easy and fun to operate, is low maintenance and does not seem to harm the environment, fish are indeferent and it only uses compressed air. On a typical dive of about 30' deep, you can stay submerged for about 45 minutes and still shoot 300 shots or so with out issues of air exhaustion.