Kate's bucket on the cover of The Mysterious Benedict Society

Kate is said in the very first book to carry a fire-engine red bucket. In the second book this bucket has a lid, as designed by Milligan. It's said that he suggested a utility belt, but according to Kate "you can't stand on a utility belt to reach things" and to Reynie "or fill it with water and drop it on pursuers," a reference to the first book. This bucket is very precious to Kate and she is never seen without it, regardless of circumstance. She even drags it behind her when traveling through vents, a favorite form of transportation.

Kate's bucket contains:

  • An excellent spyglass disguised as a cheap kaleidoscope* 
  • A slingshot
  • Marbles for the slingshot (Which she used to shoot at and hit Martina)
  • A Swiss Army Knife
  • A bottle of extra-strength glue
  • A spool of clear fishing twine
  • A pencil and eraser
  • A horseshoe magnet
  • A long nylon rope
  • A flashlight
  • A penlight

In the second book, Kate has added:

  • A bottle of lemon juice for writing down invisible messages
  • A paintbrush
  • A falconry glove
  • Falcon treats and raw meat [for Madge (Her Majesty the Queen)]
  • Numerous keys for various doors around the Wetheralls' farm - later, Kate uses one of them to trick a Ten Man.

In the second book, her bucket also has pouches on the sides (attached with the extra-strength glue and made out of the shirt "Number Two" gave her) to carry her objects.

This spyglass is used throughout the books, and the fact it is disguised, helped them numerous times.  In book one, the Executive Jackson found Kate looking through the spyglass on the island, and he demanded to see it.  She gave it to him, and he made fun of it because it looked like a cheap kaleidoscope.