I have four of the wonderful Pure Audio Project OB-A15neo (SEN) for sale.
These were mounted and played briefly but are not yet broken in. A wonderful sounding OB specific woofer that is extremely fast, detailed and lively.
More info here: http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/
Google these and there will plenty of rave reviews to read up on.
My price is for all four woofer shipped in the CONUS only.
Buy with confidence from a trusted A'goner.
Thanks for looking!