It is a transparent film bonded directly onto the glass panel by means of an adhesive to improve safety by retaining the pieces together in the event of glass breakage. S.R.T. film provides an added layer of security for you and your family. In the event of an accident, S.R.T. prevents the tempered glass door from shattering into thousands of pieces which could cause damage. S.R.T. is very durable. It has been tested for long-term usage against chemicals and abrasives and meets the required standards. There is no special requirement for cleaning an S.R.T. treated shower door. Cleaning with a damp cloth using a mixture of vinegar/mild soap with water is recommended.