The guiro is a Puerto Rican percussion instrument with an open-ended hollow gourd with parallel notches cut in one side. This Guiro Tone Block is 7-3/4 in L x 2 in W of maple hardwood finished in high gloss mahogany. Make a sharp deep tone by striking the block with the mallet. A guiro (ratchet-like) sound can be made by scratching the beaded barrel with mallet handle.