Sentence:  The instrument a <WSD>dowser</WSD> uses is called a dowsing rod, dowsing stick, doodlebug (when used to locate oil), or divining rod. Almost any item can be used for this  purpose: a birch twig, a whalebone, and even a hanger. 
Meaning of the word marked with <WSD> tags:  One who uses the dowser or divining rod.