Ilford Multigrade filter kit set - CAT 624 214 - Blackroom enlargement filters

Description

Ilford Multigrade filter kit set - CAT 624 214. Gelatin Filter Set 3 x 3" with Holder
'Contrast control with multigrade and variable contrast black & white photographic papers can be achieved in several ways. One of the most widely used ways is through the use of multigrade or variable contrast hand filters.
A magenta filter absorbs green light and transmits blue;
A yellow filter absorbs blue light and transmits green.
In this way, high and low contrast images can be made.
Ilford produces twelve Multigrade filters that are numbered 00 - 5 in 1/2 steps, with the lowest filter number corresponding to the softest contrast.
Multigrade filters are very easy to use: no complicated calculations are needed when changing from one filter to another. The exposure time for filters 00 - 31/2 is the same; that for filters 4 - 5 is double.'
Comes with 12 filters, holding case, filter holder, and adapter. Instructions (they are in Japanese) but there is a multilingual booklet with illustrations and description of contents.
re: the 'below lens red filter'; there is a red translucent 2.25" x 2.25" piece of plastic, which may be the 'red filter'. I'm not sure if that is what that piece is for, but it seems to be that filter.
The filters all seem to be in good to very good condition. There doesn't appear to be any scratches on them. They appear dusty and should probably be cleaned off before use. One filter, No. 4 has a small, approx 2 mm smudge near the edge of the film.