Meet the Zap Cap. Once billed as the World’s Greatest Opener, I’ve had one of these on my countertop since 1997. We loved the plastic white opener so much, I purchased its stainless steel cousin a couple years later. We loved this opener so much, I gave it to my groomsmen along with a couple other gadgets when I married in 1999.
This is a plunger opener, whose design has either been stolen or rebranded many times since. It is holds a Japanese patent dated 1980 by Hiroshi Kichijyo (ref US patent 4414866). Cellardine is listed as the seller on my plastic opener. I’ve also seen newer Chinese versions listed as the Bottle Hammer, Bottle Popper, Be Open Soda and Beer Bottle Opener, MyTopOff, and Easy-Open Bottle Opener.
Its function is relatively simple. You rest the opener over the neck of the bottle and press down firmly and pop up in a firm plunging motion. The opener pops the cap and holds it with a magnet. When you remove the opener, the cap follows. No more chasing rogue caps across the counter or floor.
Whenever this opener is busted out in front of guests, a conversation usually follows. The more enthusiastic guests may suddenly become chivalrous and offer to fetch a drink for their spouse to try it themselves. Rookies may need 3 or 4 plunges to remove the cap, but with practice it should work with a quick double-pump for most bottles. The Zap Cap does struggle with short necked bottles since it requires nearly two inches (5 cm) of clearance for plunging.
This opener has worked great for years. We did replace a plastic model after several years of use, but the replacement has held fast for a decade since with limited use. We’ve had no issues with the stainless steel model. Others have reported different success. This may be due to their lack of seasoned plunging technique or perhaps quality control is not what it could be in China.
Summary
Does it open? Absolutely. Although, your mileage may vary depending on manufacturing and quality control.
Can it open anything else? Doubtful. Since it has no sharp edges and is pretty light, I can’t imagine what other use it could have beyond popping caps.
Overall rating: 
(4 / 5). This opener works and delivers a wow factor that will attract attention from even the most apathetic houseguests.
References: S-4 in JFO type index.