Fotodiox 6x8-Blue-ND6SE Pro 6.6 x 8.5 Inches Graduated Density 0.6, 2-Stop Soft Edge Filter, works with WonderPana 66 and FreeArc Systems (Blue) Premium grade optical polycarbonate (CR39) filter High quality, super thick, gradient filter Blue brings realistic color into flat skies Gives a deeper effect to skies 24 Month Manufacturer Warranty