Rated 1 out of
Big Stopper fails"This filter is NOT 100mm by 100 mm as advertised by Lee. It is 99 mm x 99mm, which means it will not properly secure in a 4x4 or 100mm x 100mm standard filter holder.
Proper 100m x 100m are actually sized at 101 mm square, to ensure a good fit.
Also - this glass is nearly half the thickness of a Tiffen filter.
AND it is fitted with a foam ""seal"" around the perimeter - which indicates it is most likely intended to be used with a propietary holder, although the literature makes no mention of this.
I am returning mine for an exchange or refund. It does not seem worth the price."