A 2 stage mast forklift, also known as a duplex mast, is a lift truck with a two-section vertical lifting assembly consisting of one stationary outer rail and one sliding inner rail. It offers higher lift than a simplex mast while maintaining a relatively low collapsed height, making it ideal for double-stacking, cross-docking, and working in confined spaces such as containers.
Key Specifications
Lift heights for 2 stage masts typically range from 118 inches (3,000 mm) to 180 inches (4,572 mm) depending on the model and configuration. A 2026 Harlo HP6500 with a 2-stage mast offers a maximum lift height of 180 inches and a lowered height of 124 inches. Yale's 2-stage LFL mast provides maximum fork heights from 118 inches (3,000 mm) to 236 inches (6,000 mm) with lowered heights ranging from 100 inches (2,540 mm) to 164 inches (4,165 mm). The Clark CGC70 comes standard with a 2-stage mast offering max fork heights around 159 inches.
Free lift is typically limited to approximately 6 inches (160 mm) for standard 2-stage masts. This means the forks can rise only a short distance before the mast itself begins to extend. Full free lift options are available on some models, offering up to 160 mm of free lift.
Types of 2 Stage Masts
Limited Free Lift (LFL) provides minimal fork movement before the mast extends. Suitable for applications with adequate overhead clearance.
Full Free Lift (FFL) allows the forks to rise without the mast channels moving. Ideal for low-clearance environments such as trailers and containers.
Advantages
Higher lift than simplex – Reaches up to 15–20 feet, suitable for double-stacking.
Lower collapsed height – Easier to maneuver through doorways and under low ceilings.
Cost-effective – Less expensive than 3-stage or 4-stage masts.
Free lift capability – Enables operation in confined spaces.
Limitations
Limited lift height – Not suitable for high-bay warehouses requiring lifts over 20 feet.
Reduced free lift – Standard models offer only ~6 inches of free lift, less than triplex masts.
The bottom line: A 2 stage mast forklift offers lift heights from 118 to 180+ inches with a lowered height typically under 130 inches. It is ideal for double-stacking, cross-docking, and container work. Choose limited free lift for open areas or full free lift for low-clearance environments. For high-bay warehousing over 20 feet, a triplex mast is recommended.