Aero Classic Heavy Duty Rib Tread 10x3.50-4 6PR or 10​/​3.50-4 6PR 10​/​3.50-4 6PR - Heavy Duty Rib Fit: Scott 3400​/​3450 Tailwheels Aero Classic has been manufacturing aircraft inner tubes for over three (3) decades. Aero Classic tires and tubes are the mainstay and preferred choice for Warbird, Experimental, General Aviation, Specialty and rotorcraft with worldwide distribution and support. Metric and Tire​/​Tube sizes that fit most Vintage, Warbird, General Aviation, Experimental, LSA, Microlight, Glider and Sailplane and Eastern Bloc aircraft.