Panelboards. Spectra+ Series Panelboards. Module includes fusible switch and panelboard mounting connectors. Fuses not included. Class R Fuse Clip Kit (for field installation) included with all switches that accept Class R Fuses. FP suffix indicates that all AFP filler plates are included to fit applicable box widths. Branch Switch Modules Plug-In Spectra+ 600 Volts 3-pole. Fuse Type: H, R, J, or K. X height: 4X. Note: 1X = 1 3/8" vertical panel space. Side Filler Plate Kit Part Number: AFP4X. Box Width Range: 36", 44".