Traveler® L4 Folding Wheelchair 18" x 16" Seat The Traveler® L4 is a high-strength lightweight K0004 Medicare coded wheelchair. The Traveler® L4 has dual axles and multi-position caster forks for an adjustable seat height of 18 or 20"es. The wheelchair comes standard with non-marking polyurethane tires, anti-tippers and a chart pocket.