Just received these and using them as I type. Great for when you have multiple wines open for whatever reason. By pumping the air out, you keep the wine as fresh as if new each time you open of another glass.Somehow I keep loosing these. Love them!Fits well in your standard size wine bottle. It seems to seal completely and keeps the wine fresh. They are pretty plain, so I wouldn't really call them giftable, but it's nice to have them on hand at home.I did not have much hope for these, but I go them anyway. Boy was I surprised these really worked and plus having these stoppers in the wine bottle, they actually fit into my fridge now it was so hard to put the wine stopper back in there and keep everything fresh and cold and be able to put it back in my fridge it does not work, but for these little black wine stoppers they are awesome. I love them.The design of these stoppers makes them easy to use on open wine and other bottles. I don't know what the "ribs" on the side are called, but they seem to be well designed as far as ease of use and security of the seal is concerned. I didn't do a long-term test of how long it will keep the contents of a bottle fresh, but it works very well short term.The description was a bit confusing and I thought I was getting a pump, too. Turns out, it was just a package of 4 stoppers. So i looked around and found another pump that looked like it used the same stoppers. They worked! Turns out the good news about all these guys copying each other's designs means that there is parts interchangeability.I was a bit worried that these wine savers wouldn't be compatible with our old wine pump that I purchased years ago here on Amazon: https://www.amazon.com/gp/product/B08GC3DBCW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1Although it is no longer available, they should work with similar wine pumps.I was able to pump until I heard the "click", and no wine leaks out when the bottle is turned to the side.Very secure suction.This is a very good deal for 4 savers. Recommended.Worked well and hold a seal.