GTCHAIR 3D dynamic back-lumbar Support Office Ergonomic Task Chair

Specifications and material:  Dimensions: 31.5"×17.3"×26" (W×D×H) Color: black and red Plastic Shell: Black PA engineering plastic + glass fiber 30% + 13mm super thin back design Aluminum Part: ADC#12 black paint coated strengthen aluminum alloy Back(Headrest) Cover: High elastic Korean Wintex GT Mesh with PU/ Leather Combined Lumbar Support: High density foam pad upholstery Seat: High elastic Korean Wintex GT Mesh with PU/ Leather Combined Armrest: Paddle shift wire control, PA Engineering plastic arm frame + glass fiber 30%, PU cover Mechanism: 60Si2Mn Double Spring Paddle Shift Wire Control Mechanism, aluminum shell with texture baking finish, anti-corrosion and abrasion resistant Gas Lift: Customized Korea Samhongsa class IV 85mm drive, load-bearing 250kg Base: BIFMA Certified 350mm ADC12# black paint coated aluminum base with reinforce rib and noise reducing caps inside  Casters: BIFMA Certified 65mm black PU casters, rolling test for 100,000 times Bolts: Grade 12.9 hyper-strength bolts in key parts. Function: Backrest: Height adjustable for 3 level in 4cm and backrest tilt can be locked in 15 positions within 33 degrees by arm paddle BAS System (Back Automatic Supporting System): Without any adjustment, the upper backrest can provide a 10 degree torsion support and lumbar support offering 15 degrees automatic waist rotating Seat Height: Height is adjustable within 7cm by arm paddle Seat Sliding: Seat depth adjusted within 5cm 5 levels Armrest: Height adjusted within 5cm for 5 levels and pivot in 3 directions within 30 degrees Mechanism: Backrest tilt tension adjusted by the rocking handle under the right side of the seat and laser coding for 5 years warranty S3-L Headrest: Rotation, angle and height adjustment Paddle Shift Wire Control System: The backrest tilt lock and seat height are controlled by mechanism via the paddle on the arm Shipping: Ships in 5-6 weeks