The Intruder Box(TM) Until now, we simply couldn&';t find a box to hold a bunch of unruly intruder-style flies for our steelhead outings. After a period of deep thought, intense concentration, and round-table discussions with the Cliffitarians, we decided that a memory coil system was just the ticket. Simply back the stinger hook into our time-tested blue material and place the head of the fly under the memory coil. Ta Da! Problem solved. This is The Box for Intruder style flies (it holds other flies too). This box comes with a size of 10" X 6 A 1/2" X 2 3/4".