Inline duct filters are disclosed herein. The adjustment operation is performed in such a manner that: a first image, that is used for detecting scanning error of an image scanning device, is formed on an image carrying body and then transferred from the image carrying body to the sheet, the first image being formed over at least three corners of the sheet while extending outside the sheet. The packaging further includes an outer exterior having an integral flap. The window assembly may include conductive heater grids that are electrically powered without use of jumper wires that electrically connect between heater grids of the fixed window panel at opposite sides of the movable window panel. An insert is positioned between the trigger guard structure and the stock structure for ensuring a tight fit and preventing contact therebetween. The iron-based powder includes a mixed iron powder of atomized iron powder and reduced iron powder.