Complex sentence: Some guitars (notably Rickenbackers) come with dual truss rods that are more stable and not affected by seasonal climate changes, they are also more difficult to adjust and should be serviced by a professional.
Split into simpler sentences: Some guitars (notably Rickenbackers) come with dual truss rods that are more stable and not affected by seasonal climate changes. They are also more difficult to adjust and should be serviced by a professional.