I orginally posted this item for $70, thinking they sold new for $110. I came across my receipt and they sell new for only $78. So my price is down.
The clear aperture of this filter is 4". The inside diameter of the aluminum cell measures 5.25", 131mm without the felt lining. Wiht the felt strips in it as it sits now, it fits the Celestron/Synta 102mm scope, or any 4" scope with a dewcap measuring 131mm or less. I think I used it twice. The rest of the time it was put away in its box.
$53 plus shipping