Tank Banger - Signaling Devices

A simple, effective form of underwater communication. Just slide it around your tank, grab the bright yellow knocker and bang away. Great as a general underwater attention getter. Durable solid rubber band for longer life.

Warning: Please resist the temptation to put this around your spouse's head, (both above and below the water) even though it's really funny. The knocker is made from hard plastic and will hurt them a lot. Then, when you least expect it (like when you are sleeping) they'll do it back. No seriously, head trauma is no laughing matter.