Know more about Combo-search Combo-search enables you to switch your browser's default search engine. Simply click on the Combo-search icon in the Firefox extensions bar and select the search engine that best suits what you need from the list and click 'Set'. Combo-search Firefox extension is free to download directly from the Firefox Web store. Our service will provide you with a choice of the most popular and well regarded search engines, leading to better targeted search results, letting you discover more of the web and giving you access to the most relevant content. Our basic version of the service will be offered free of charge.