The FULLERPHONE was invented by Capt AC Fuller British Army to resolve a “Eavesdropping” problem by the enemy in 1915. This model was introduced in 1939 and several other MK variations followed later on.Fuller phone MKIV, green wooden box with metal hinged lid, steel strapping around box & lid. Steel handles on 2 sides. Inside is the phone apparatus. On the lid inside is metal plate with instructions on use.“Fuller Phone MKIV 2005”military equpment - communications, communications - telegraphic, fuller