OK, but unsophisticated. 1) there are no labels for searches so you have to rely on the icon, which is very small. 2) if you do not provide and icon when you add a new search it will not be saved. Most such extensions are able to extract icons from sites like Amazon. 3) You can't change the size of the bar or it's placement. It always shows under the default Opera Search/Copy pop up. Annoying.
Otherwise, it functions very well.