I have three Garden Metal Models 12" ABS plastic simulated concrete piers.
The are designed as a pier for any bridge but also have adapters to specifically fit the GMM bridges.
They will go on Ebay on Sunday December 14 and are offered here till then.
Note for longer piers the 24" and 36" extensions appear to still be available at Charles RO
I am selling each pier for $25.00 plus shipping
Thanks
Stan