Series VI drop in filter

I have a Series VI drop in filter that is older but works great in an SCT. This is from my older C-8 and I am getting out of planetary observation. I have a green filter and am going to be digging out others. You unscrew the eyepiece holder from the sct and place the filter in there. It is very nice if you plan to take astrophotos since you can still use the telescope in prime focus. I don't remember how much I paid for the filter so I am asking $10, shipping included. I know I paid more than that so I am just being safe. This is for the green filter only. I will be posting more later. Thanks.