The mast, also called the upright, is the vertical assembly on a forklift that lifts, lowers, and positions loads. It consists of nested steel rails, a hydraulic system, and the carriage that holds the forks. Choosing the right mast is critical for maximizing your warehouse's vertical storage and operational efficiency.
The Four Main Mast Types
Mast Type Stages Best For
Simplex (Single-Stage) 1 Basic tasks, low lift heights, outdoor use
Duplex (Two-Stage) 2 Double-stacking, cross-docking, low-clearance areas
Triplex (Three-Stage) 3 General warehousing, the most common and versatile mast
Quad (Four-Stage) 4 Specialized very high stacking, advanced operator training required
Key Mast Terminology
Free Lift: The distance the forks can rise before the mast itself begins to extend. Full free lift masts are essential for working inside trailers and low-clearance areas.
Lowered Height: The mast's height when fully collapsed. Critical for fitting through doorways and under low ceilings.
Maximum Fork Height: The highest point the forks can reach. Always add at least 6 inches of clearance above your tallest racking shelf.
The bottom line: The mast is the vertical lifting assembly of a forklift. The four main types—Simplex, Duplex, Triplex, and Quad—offer increasing lift height and complexity. Triplex masts are the most common for general warehouse use. When selecting a mast, prioritize free lift for low-clearance work, collapsed height for facility access, and maximum lift height for your racking system.