Review on Preserve Wine Freshness with Premium Wine Pump Preserver Saver Kit by Devon Holmes

I've been using these corks for years to keep partially filled wine bottles fresh. This one basically doesn't hold a print for more than a few hours, which means it's not doing its job. The previous plugs I had were grey, I still have some of these and they work great. These plugs are black material, I don't know what that color means. Another material that doesn't seal as well? I've noticed that corks sometimes work with red wine that isn't chilled - I wonder if the material the corks are made of works better when it's not cold and maybe less hard. In any case, due to my several months of efforts to get it working, the product is not working as advertised.