The Tiffen 6.6 x 6.6' Digital Diffusion/FX 3 Filter is a softening and diffusion filter specifically meant to appear invisible, as if no filtration is being applied.
6.6X6.6 DIGITAL DIFF FX2 - W6666DDFX2
66X66 WW CLEAR 4K TITANIUM MC - W6666CLR4KTIMC
6.6X6.6 WTR/WHT CLR/ND.9 SE - W6666CGN9S
6.6X6.6 WTR/WHT CLR/ND.9 HE - W6666CGN9H
6.6X6.6 WTR/WHT CLR/ND.6 HE - W6666CGN6H
WW 66X66 BLACK GLIMMERGLASS 2
WW 66X66 BLACK GLIMMERGLASS 1 - W6666BLKGG12
WW 66X66 BLACK GLIMMERGLASS 1 - W6666BLKGG1
WW 66X66 BLACK PEARLESCENT 1 - W6666BKPEARL1
6.6X6.6 WARM PRO MIST 1/8 FILTER - 6666WPM18
6.6X6.6 WARM BLACK PRO-MIST 1 - 6666WBPM1
6.6X6.6 ULTRA CONTRAST 1/8 FILTER - 6666UC18
6.6X6.6 ULTRA CONTRAST 1/2 FILTER - 6666UC12
6.6X6.6 TOBACCO 1/8 FILTER - 6666CO18
6.6X6.6 TOBACCO 1/4 FILTER - 6666TO14
6.6X6.6 TOBACCO 1/2 FILTER - 6666TO12
6.6X6.6 TOBACCO 1 FILTER - 6666TO1
6.6X6.6 TANGERINE 2 FILTER - 6666TA2
6.6X6.6 TANGERINE 1 FILTER - 6666TA1
6.6X6.6 STREAK 2MM HE FILTER - 6666STRK2H
6.6X6.6 STREAK 2MM FILTER - 6666STRK2
6.6X6.6 STREAK 1 MM FILTER - 6666STRK1
6.6X6.6 STRAW 3 FILTER - 6666SEP1
