Features: Never Wonder Again If Youre Sanitizing Hard Surfaces Properly. New Sertun Rechargeable Sanitizer Indicator Towels From Itw Professional Brands Will Give You Unmatched Confidence In Your Sanitizing. Using Our Patent-Pending Color Check Technology, Sertun Towels Give You Complete Assurance That You Are Truly Sanitizing Hard Surfaces. Think Of It As A Quaternary Ammonia (Quat) Test Strip Embedded In A Disposable Foodservice Wiper. Sertun Towels Change From Yellow To Blue When Proper Quat Levels Are Present In The Sanitizing Bucket And In The Towel. As The Towel Deploys Quat, The Color Changes From Blue To Yellow, Indicating There Is Not Sufficient Sanitizer In The Towel.