From the Foster Coach Sales Facebook page:

2017 Horton conversion on a Ford F-550 chassis
Park Ridge FD ambulance

Foster Coach Sales photo

Park Ridge FD ambulance

Foster Coach Sales photo

Park Ridge FD ambulance

Foster Coach Sales photo

Park Ridge FD ambulance

Foster Coach Sales photo

Park Ridge FD ambulance

Foster Coach Sales photo

new ambulance interior

Foster Coach Sales photo

From Bill Smaha:
Because the other two ambulances are less than 2 years old, this ambulance did not have any vehicle designation assigned. This will come at a later date.