Vibration damping apparatus

A vibration damper apparatus comprising:

• a rotatable hub;
• a first inertia member rotatably supported within said hub for relative rotation thereto including a first mass portion having a first thickness and a second mass portion having a second thickness, said first mass portion thickness having less thickness than said second mass portion;
• and
• a second inertia member rotatably supported within said hub for relative rotation thereto including a third mass portion having a thickness substantially equal to said first mass portion and having a fourth mass portion having a second thickness substantially equal to said second mass portion and being axially aligned with said first mass portion;
• wherein said first inertia member includes a pair of first flat radially projecting surfaces each extending from an inner periphery of said first inertia member to an outer periphery of said first inertia member;
• and
• wherein said second inertia member includes a pair of second flat radially projecting surfaces each extending from an inner periphery of said second inertia member to an outer periphery of said second inertia member, said pair of second flat radially projecting surfaces opposing the first pair of radially projecting surfaces for rotatably coupling the first inertia member to the second inertia member to prevent said first inertia member from rotating relative to said second inertia member.