HOIST Commercial Duals HD-3900 Butterfly / Rear Delt Machine

The HOIST HD-3900 Pec Fly / Rear Delt machine from the Commercial Duals series is a prime example of cutting-edge American engineering and uncompromising biomechanics, designed for elite fitnessresidents, premium wellness spaces, and high-end home gyms. Thanks to the Dual Functionality concept, the equipment flawlessly combines two anatomically isolated movements into a single elegant unit, efficiently optimizing the strength training area without compromising ergonomics or effectiveness.

Aesthetics and structural perfection:

• Premium frame architecture: a solid steel profile with electrostatic powder coating and a durable lacquer finish integrates seamlessly into modern high-end interiors.

  
  

• Ergonomic upholstery: premium-grade, wear-resistant vinyl leather with high-density double stitching resists deformation and retains its impeccable appearance even under intense commercial use.

  
  

• Acoustic comfort and smoothness: Precision sealed bearings and nylon-reinforced polymer rollers ensure virtually silent operation of the weight stack.

  
  

Innovation and biomechanics:

• Independent self-adjusting levers (Dual Pivot Arms) $\→$ allow the handles to freely adapt to the athlete’s individual arm length, relieving traumatic torsional stress from the elbow and shoulder joints and directing the entire resistance vector exclusively to the target muscle fibers.

  
  

• The multi-position Range of Motion Adjuster (eccentric selector) quickly switches the angle of the arms from the backward abduction position to the forward adduction position $\rightarrow$ and ensures a physiologically correct range of motion and a constant load curve during the concentric and eccentric phases of movement.

  
  

• The ergonomic contoured chest and back pad—a two-position support—maintains physiological spinal alignment during chest presses or reverse flyes, eliminates unwanted torso movements, and enhances isolation of the target muscle groups, includingthe deltoid and pectoral muscles.

  
  

• Pneumatic seat height adjustment—a smooth mechanism—sets the seating position for any height with a single motion $\rightarrow$ allows you to quickly lock in the correct shoulder alignment relative to the machine’s axis of rotation.

  
  

3. Features and Specifications (Attributes)

Parameter

Value

Equipment Class

Professional (Commercial Heavy-Duty / Premium Home Gym)

Intended Use

Bringing arms together in front of the body (“butterfly” / chest muscles), abduction to the rear deltoid

Dimensions in operating position (L × W × H)

$145 \times 130 \times 188\text{ cm}$ ($57" \times 51" \times 74"$)

Machine Weight (Net)

239 kg (527 lbs)

Weight stack weight

100 kg (220 lbs) with magnetic weight selection pin

Frame materials

High-strength structural steel with a powder-coated finish

Upholstery and filling

High-density, anatomically contoured polyurethane foam; premium, wear-resistant vinyl

Electrical Specifications

Mechanical resistance trainer (no power connection required)

Maximum user weight

180 kg

Country of brand registration

United States

Official warranty

10 years on the frame, 2 years on components and moving parts, 1 year on upholstery