Bottle openers are needed to open many bottles. As soon as the commercial bottle was invented, the opener to be used with the new types of closures became a necessity. The current bottle opener was invented at the same time as the cap. There have been crown bottle openers, bar blades, and other designs—tools to open their bottles. Many types of bottle openers can be found, most dating from the twentieth century. Collectors prize unique designs, advertising and comic openers.