Protective Industrial Products Miller® DuraHoist™ Lower Mast Extension

Product Description

The Miller DuraHoist Lower Mast Extension is part of a versatile two-piece mast system designed to deliver expanded solutions for height-restrictive applications where the DH-3 one-piece mast alone may not offer sufficient reach or clearance. Working in combination with the Miller Adjustable Offset Upper Mast (12"–29"), this lower extension enables a wide range of configurations that support complex access, rescue, and confined-space requirements. This system allows the mounting of multiple winches and/or self-retracting lifeline (SRL) systems, making it highly adaptable to various jobsite demands. Thanks to its tool-less design, the mast breaks down into lightweight and manageable components that simplify transport, storage, and setup—an essential benefit for crews that frequently move equipment between locations. Constructed from welded aluminum with AWS-certified welds, zinc-plated hardware, and a safety-yellow powder-coat finish, the lower mast extension offers excellent durability, corrosion resistance, and long-lasting performance in industrial environments. It is fully compatible with Miller DuraHoist davit systems and maintains the strength needed to satisfy all rated proof-load requirements.

Features:

• Works with the Miller Adjustable Offset Upper Mast (12"–29")
• Ideal for height-restricted applications requiring extended mast configurations
• Compatible with Lower Mast Extensions DH-21 and DH-22
• Supports mounting of multiple winches and SRL systems
• Tool-less, lightweight design for fast setup, transport, and storage
• Allows various component configurations to meet application needs
• Safety yellow powder-coat finish for increased visibility

Materials:

• General Construction: Welded aluminum
• Weld Certification: AWS
• Hardware: Grade 5, zinc-plated
• Material Structure: 6061-T6, 5052-H32, 7075-T6 aluminum
• Block Anchor: 304 stainless steel
• Finish: Safety-yellow powder coat

Technical Specifications:

• Rated Capacity: 450 lbs. (204 kg) working load limit
• Minimum 4:1 design factor

Proof Load Ratings /Anchor Points:

• Pin Position 1 & 2: 5000 lbs.(22 kN)
• Pin Position 3: 3600 lbs. (16 kN)
• Pin Position 4: 3000 lbs. (13 kN)
• Optional Anchor: 5000 lbs. (22 kN)

Winch/SRL Mount Positions:

Rear Mount:

• Pin Position 1 & 2: 5000 lbs. (22 kN)
• Pin Position 3: 3600 lbs. (16 kN)
• Pin Position 4: 3000 lbs. (13 kN)

Front Mount:

• Pin Position 1 & 2: 2500 lbs. (11 kN)
• Pin Positions 3 & 4: 1800 lbs. (8 kN)
• Weight: 23 lbs. (10.5 kg)