Chapter 4 - Internal filters for modified cameras - Standard Infrared Filter - Infrared Conversions, IR Modifications & Photography Tutorials | Life Pixel IR
Best Buy: Cokin P007 Infrared 720 89B Filter CP007
Cokin Infrared 89B Filter Series Z - Walmart.com
Cokin P Series Infrared Filter Kit - H1H0-27 – EventCameras
17 - On-Lens Forensic IR Filter (Wratten #89B) :: Spencers Camera
Working with Wratten Filters and Infrared Photography | JoeFarace.com
File:Dunsapie Loch seen through 89B Infrared 720nm filter.jpg - Wikimedia Commons