THUNDERX3 FLEX Pro Ergonomic Office Chair

Assembly Manual

Parts List

Before you begin assembly, please identify all parts:

Seat Cushion
Backrest
Seat Mechanism
Gas Lift Cylinder
Casters (5x)
Star Base Legs (5x)
Allen Wrench

Hardware:

Screw A: M5 M1/4 x 3/4" (10 pieces)
Screw B: M5 5/16 x 7/8" (3 pieces)
Screw C: M5 M1/4 x 7/8" (2 pieces)

Assembly Instructions

Follow these steps carefully to assemble your FLEX Pro chair:

Step 1: Attach Base Legs

Attach the five star base legs to the central hub of the star base. (Diagram shows legs slotting into the base center).

Step 2: Attach Seat Mechanism to Seat Cushion

Align the seat mechanism with the pre-drilled holes on the underside of the seat cushion. Secure it using 4x Screw A. (Diagram shows mechanism being screwed onto the seat base).

Step 3: Attach Armrests to Seat Cushion

Align the armrests with the mounting points on the sides of the seat cushion. Secure each armrest using 3x Screw B. (Diagram shows armrest being attached with screws).

Step 4: Place Seat Assembly onto Gas Lift

Carefully place the assembled seat and backrest unit onto the top of the gas lift cylinder. (Diagram shows the chair base being lowered onto the gas lift).

Step 5: Attach Backrest to Seat Mechanism

Align the backrest with the rear mounting bracket of the seat mechanism. Secure it using 2x Screw C. (Diagram shows backrest connecting to the seat mechanism).

Step 6: Adjust Backrest Angle

Use the lever to adjust the angle of the backrest. (Diagram shows a lever and a curved arrow indicating backrest movement).

Step 7: Tilt Backrest Forward/Backward

Tilt the backrest forward and backward to find a comfortable position. (Diagram shows a curved arrow indicating tilt motion).

Step 8: Adjust Backrest Height

Adjust the height of the backrest by operating the designated lever or mechanism. (Diagram shows vertical arrows indicating height adjustment).

Step 9: Adjust Backrest Height

Further adjust the height of the backrest as needed. (Diagram shows vertical arrows indicating height adjustment).

Step 10: Lock/Unlock Tilt Function

Use the provided controls to lock or unlock the chair's tilt function. (Diagram shows lock and unlock symbols with rotation arrows).

Step 11: Adjust Seat Height

Operate the height adjustment lever (usually under the seat) to raise or lower the seat. (Diagram shows lever operation and vertical seat movement).

Step 12: Adjust Armrest Rotation

Rotate the armrests to your preferred position. (Diagram shows armrest rotating outwards/inwards).

Step 13: Adjust Armrest Forward/Backward Slide

Slide the armrests forward or backward to find the most comfortable position. (Diagram shows armrest sliding horizontally).

Step 14: Adjust Armrest Height

Adjust the height of the armrests to suit your needs. (Diagram shows armrest moving vertically).

Step 15: Adjust Lumbar Support Rotation

Rotate the lumbar support knob to adjust its position. (Diagram shows a knob being turned).

Step 16: Adjust Lumbar Support Height

Adjust the height of the lumbar support. (Diagram shows vertical movement of the lumbar support).

Step 17: Adjust Tilt Tension

Turn the tilt tension knob to increase or decrease resistance when reclining. (Diagram shows a knob with '+' and '-' symbols, indicating tension adjustment).

Step 18: Lock/Unlock Tilt Function

Use the controls to lock the chair in an upright position or allow it to recline. (Diagram shows lock/unlock symbols and rotation).

Step 19: Adjust Seat Depth/Slide

Slide the seat forward or backward to adjust the seat depth. (Diagram shows seat sliding horizontally and a lever).

Usage Guidelines

Cleaning Instructions:

Keep the chair tidy by vacuuming its seams regularly.
Avoid using harsh cleaning chemicals such as acetone.
Avoid direct sunlight.

Intended Use and User:

Not suitable for children under 8 years old.
Maximum weight capacity: <125 KG.

Maintenance and Repair:

After approximately 1 week of use, check that all screws are properly tightened.
Do not attempt to repair this product yourself, especially the gas lift.

Specifications

Specification	Details
Recommended Height	160cm - 190cm (5'3" - 6'3")
Maximum Weight	<125kg
Temperature Interval at Usage	+50 to +104 °F / +10 °C to +40 °C
Temperature Interval at Storage	0 to 158 °F / -18 °C to 70 °C
Humidity	20% to 80% at 104 °F/40 °C

Disposal and Recycling

The FLEX Pro should be disposed of separately from household waste. It must be handed in for recycling in accordance with local environmental regulations for waste disposal. By separating the FLEX Pro from household waste, you help reduce the volume of waste sent to incinerators or land-fills and minimize any potential negative impact on human health and the environment.

Warranty Information

Please prepare the following information before contacting your point of purchase or local agent:

Invoice/receipt.
Photo of the serial number (starts with SN, found underneath the product).
Photos or video of the product illustrating the problem/issue.
Photo of the complete product.

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