Howland Type 4 Lamp
Howland Type 20 Lamp
Howland Type 21 Lamp
Howland Type 22 Lamp
Howland Type 23 Lamp
Howland Type 24 Lamp
Howland Type 25 Lamp
Howland Type 27 Lamp
Howland Type 28 Lamp
Howland Type 29 Lamp
Howland Type 30 Lamp
Howland Type 32 Lamp
Howland Type 33 Lamp
Howland Type 34 Lamp
Howland Type 36 Lamp
Howland Type 40 Lamp
Howland Type 42 Lamp
Howland Type 43 Lamp
Howland Type 44 Lamp
Howland Type 45 Lamp
Howland Type 48 Lamp
Howland Type 51 Lamp
Howland Type 54 Lamp