Sixty years ago this month, the May 1959 issue of Popular Mechanics shows an idea that surprisingly never caught on: underwater music. You’re swimming at the pool and listening to music. But when you dive under the water, you can no longer hear the music. The problem is easily solved by installing a speaker inside the pool. Because sound travels five times as fast in water, “music from the submerged speaker is more true-toned than one mounted in the air.”

And the project is quite simple. All you need to do is purchase a “submergence-proof speaker.” The magazine recommended the University MM-2F (UW), a 25 watt speaker which sold for about $40.

And lo and behold, if you search Amazon for “submergence proof speaker,” one is still available today, although it appears to be marketed toward industrial applications. It is shown here, and the full details are available at this link.  It appears quite similar to the model shown in the magazine.  The price is higher today than it was in 1959, although most of the increase is attributable to inflation.