Signature Tea Bag - Organic Jeju Volcanic Oolong Tea 20 Count Signature Tea Bags Collection. The Osulloc signature tea bag collection invites you to experience the essence of pure organic green and black teas, or our unique blended teas, anytime and anywhere. Whether you opt for our USDA-certified pure tea range or our blended array, each comes with a promise of rare natural flavors and soothing aromas.