Thanks to this thread started by rickersjun, a new group of devices has been brought to our collective attention. I haven’t seen these “Health Stone Glass” devices before.

They use the same silicon carbide foam used in the GVG, but there’s no separate glass holder or top piece. The foam must be handled directly. Putting it into a pipe is obviously easy, but removing it could be a problem.

I also wonder how airtight the seal is. With the GVG, everything is very snug.

Anyhow, these devices use the same technology as the GVG, so my guess is that they’re just as effective and efficient. I’ve never said that about any other devices, so it seems this is the first serious GVG competitor!