Sound Transit 9090-9091 are 2005 Gillig Phantom 40' (C29D102N4) buses.
These are the third batch of Gillig Phantoms delivered for use by Sound Transit. Unlike the other Gilligs in the fleet, these two buses were modified to King County Metro Transit specifications. Each bus in the series had a cost of around $329,178 2005 USD.
These buses are planned for retirement in 2020, they are to be replaced with 60-foot articulated hybrid diesel buses.  
All buses in this series are stored at the King County Metro Transit East Base.