[tbrooke]

Finally getting around to the Series II Passive and I found this 10 inch Passive and wanted to make sure it is the right one:

https://www.css-audio.com/online-store/CSS-APR10-10-Passive-Radiator-p148179575

Looks like a good price

[GeorgeAb]

That's the one. I recall having to trim a bit of the edge of the included gasket for fitment. Seven washers was my sweet spot per my recollection, its been awhile. Greg username G E did a really nice job on providing a guide for the entire process.

[G E]

I found it easiest to remove the plastic or hard rubber gasket from the passive. It was then a perfect fit in my opening.

Be sure to use some gasket material if you remove it. I used 3M product that is intended for automotive use. Never hardens, not a glue. Refer to my write up for its name etc.

Good luck!