Research tests were conducted in 1989.
After 3 years of successful test results patents were applied for.
The first patent No. 1332541 was granted  October 22 1994 to Mr. Stephen Collins.
A second Patent No. 2456610 was issued Feb. 20 2007.
Two more patents are pending as well as US. and international TCP patents.

Amanak Ltd has been manufacturing these filters since 1989.
Amanak Ltd filters were used in  all of the test studies.
Amanak Ltd filters have remained working successfully for 20 years.
Amanak Ltd is the only license filter manufacture.
In 2003 Amanak Ltd Filters were used by Semoptics Ltd, who conducted  a $25,000 lab test program confirming  these filters remove water from failed windows restoring the R-value.

Because of this track record we can offer a real warranty.

Note:
In 2002 Crystal Clear negoitiated a license to use the patent which was cancelled in 2003 due to default of payment. Crystal Clear failed to negotiate a new license December 5, 2003.  Crystal Clear and its Dealers have not paid Mr. Collins for use of the patents for the past 5 years and is infringing the patents. Crystal Clear has not used  Amanak Ltd filters since 2004 and has never had the rights to manufacture these filters.
The following law suits  are pending against Crystal Clear and Mr. Blackburn:
Ontario Superior Court File No. 04-CV-264048  October 2003
Ontario Superior Court File No. 05-CV-31575  
Ontario Superior Court File No. 06-CV-33533