Amazon.com : Hama Circular Polarizer Filter 77mm : Camera Lens Polarizing Filters : Camera & Photo
Amazon.com : Opteka 77mm High Definition II Multi-Coated Circular Polarizing Glass Filter - Works with The Following Canon Lenses - 24-105MM, 10-22MM, 17-40MM and Nikon 28-300, 18-300 DSLR Zoom Lenses : Camera