They are acrylic bowling balls. Very hard, go very straight. Haven't been made in many years, as far as I know. I drilled one once in the later 80's or early 90's for a guy. I had to squirt water on the drill bits, while drilling, got super hot.
Don't think they were made in 16lbs. Made in Japan. I think those 14lb 7 oz were about has heavy as they would/could be made.
Tour/Regional Champ Rick Minier had one he used for a spare ball until the ball registration thing started with the PBA. I threw his in a Pro Am at a regional one time. It didn't hook much, kinda loped down the lane. Great spare ball though, on just about anything.
Not worth $1500 to me, but maybe to somebody!
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THIS SPACE FOR RENT