Appliance division of General Motors retired operations in 1964.
Service 4923592
Serial 86815
Model GBC 105H
Input 105,000 B.T.U. per Hour
Bonnet Capacity 84,000 B.T.U. per Hour
Equipped for use with NAT Gas
(output/input) 84,000 / 105,000 = 0.8
0.8 x 100% = 80%