Is there much wasted fruit between the ring and the peel?

Depends on the size of the pineapple. The larger the fruit the greater the waste. I measured the cutting blade and it is 3 1/4 inches so regardless of the size of the pineapple you will end of with a ring approximately the size of canned pineapple rings.

How do I get the core out, I went through the bottom, now the core is stuck in the handle ?

TL/DR: Use the handle of a wooden spoon. It's much safer than using a sharp implement. I bought a cheap plastic one in 2011 after coming home from "Pineapple Heaven" (Hawaii). While we were there, I bought a pineapple without ever having cut one up before. I had no idea how to skin it, so I asked the neighbor in the condo next door how to do it. He let me borrow this tool. I was amazed at how easy it was to use. I had a perfect pineapple spiral after about 30 seconds of twisting. Being a first time user, I went too far and ended up with the core in the handle and juice all over the counter (rookie mistake). After I removed the slices, I stuck the handle of a wooden spoon into the center of the tube, turned it upside down in the sink (I learned my lesson about pineapple juice) and gave the head of the spoon a gentle downward tap in the sink. The core popped right out and I didn't need to use knives or other potentially dangerous implements. As soon as we got home, I bought a cheap plastic one and it has lasted me 11 years, so far. In fact I just used it. Granted, I had forgotten I had it for several years, until I was rummaging around in a cabinet for something else. That probably helped it last longer. If you like pineapple and don't like spending your time peeling it, you want this tool. I also figured out how to contain the juices if I inadvertently go too deep. I put the pineapple in a cereal bowl when I'm ready to twist. If I accidentally go too deep, any juice that comes out stays in the bowl. I just let the shell sit in the bowl while I slice up the flesh, and when I'm done, I drink the fresh, heavenly juice. We love the juice so much, I bought a heavy duty manual fruit juicer/crusher a year or so ago. Then I slice the rind into small pieces, put each one in the crusher, and squeeze until I get all of the juice I can. I can get almost a full cup of liquid gold from a large pineapple this way. It take me a while to do, but I'm happy not to throw all of that juice away.

Is this made in China?

Hello! While our company's headquarters reside in Florida, USA, our products are manufactured in China. We're devoted to ensuring top-notch quality and your utmost satisfaction. Rest assured, our stringent quality control includes USA-based inspections for safety and excellence. We collaborate closely with manufacturing partners to adhere to all USDA and international regulations. Plus, our commitment to your contentment is solidified with a lifetime warranty for most products, coupled with 24/7 customer support. Your Kitchen Happiness is our priority, no matter where the product is made!