Just to check it out, and because it was so cheap, I just bought a Speedo Raven mask on the SpeedoUSA web site. It has slightly grater volume than a Sphera, probably about the same as a Minima. I thought it could be a back up for the Sphera I just bought. It was just under $12 U.S., and was worth about that much. Stiff, hard silicon skirt. The slightest movement of my face broke the seal even though it seemed to fit my face reasonably well. But it was so cheap the postage to send it back would be more than I'd probably get back. So now I can torture buddies who forget their own masks.
Be warned.
JB
Be warned.
JB