Amazon.com : Index Card Case, 4x6 Inch Index Card Holder, Fits Up to 100 Cards Per Case Assorted Colors - With Heavy Weight Ruled Index Cards, 4" x 6”, 100/Pack - Store
Oxford Plastic Index Card Box, 4" x 6" - ESS01461 | Tops Products | Storage
Globe-weis Index Card File Box Black Agate 1000 Card Capacity (glw 95 Bla) 194415 : Target
Advantus Index Card Holder, 5" x 8", Black - Walmart.com