GM / General Motors: 2000 Seville STS Exhaust

I have a 2000 Seville STS. Recently the left exhaust tip fell off .
I need to know where to get an oem replacement or even better a pair
of replacements.

I know I can do better than the $175. the caddy dealer wants for one
tip.

It is the squar "dual" style on each side.
thanks,
Chris