The Miller DuraHoist Three-Piece Portable Base options (DH-4 or DH-24) are constructed of lightweight powder-coated aluminum and feature
adjustable screws and a built-in level indicator for easy set-upon uneven surfaces. Three lightweight components for easy transport and storage.
No tools required.

Features and Specs:

• Three lightweight aluminum components for easy transport. Features adjustable aluminum screws and a built-in level indicator for easy set-up on uneven surfaces. No tools required for assembly.
• DH-4/ – Maximum 29-in. (.74 m) offset

Materials

• General Construction: Welded Aluminum
• Weld Certification: AWS
• Hardware: Zinc Plated
• Material Structure: 6061-T6, 5052-H32,7075-T6 Aluminum,Mild Steel, Black Acetal, Black Vinyl
• Finish:Safety Yellow Powder Coat 

Technical

Rated Capacity: 450lbs (204kg) working load limit @ minimum 4:1 Design Factor

Mast Moment Proof Load:  90,000 in-lbs (10,200 N.m)

Mast Rotation: 180°

Weights :

DH-4

• Base Center 21lbs (9.5kg)
• Base Legs (x2) 20lbs (9.1kg)
• Total 61lbs (27.7kg) 

Application Restrictions

1. All winch and block mounting parts and hardware must be supplied or approved by Miller.
2. Retractable devices or shock absorbers must be installed and used in accordance with the manufacturer’s instructions.
3. To avoid instability or tipping, the Three-Piece Portable Base (DH-4) is to be used with 29-in. (737mm) maximum offset mast (One-Piece Adjustable Mast, DH-3; Two-Piece Adjustable Upper Mast, DH-21).
4. Where required by regulation, each installation must be approved to applicable standards by a qualified engineer.
5. All equipment must be set up and operated under the supervision of a competent person according to the manufacturer’s instructions.

https://www.millerfallprotection.com/en/products/descentrescue%20and%20confined%20space/miller-durahoist-portable-confined-space-system