As the name suggests, a mandolin-guitar hybrid. Originally made by Vox, then copied by Hammertone and now produced by Phantom Guitars, which seems to own the trademark on the name as well as the body and head shapes. Other manufacturers are now calling their instruments an 'Octave Twelve'.

The double strings should give this type of instrument more of a mandolin flavour than the 6-string mandolins, but they tend to sound more like electric 12-string guitars played at the 12th fret. This is probably because no attempt is made to replicate the attack and sustain characteristics of a mandolin.