ST400F - Office Master Fabric Stacking Chair
ST400F - Office Master Fabric Stacking Chair
Disclaimer - All fabrics, arms, and other options shown are examples of available customizations. Fabric shown may not be available on all models — see product options below for current selections. Colors are approximate. Arms sold separately.
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Description
The Office Master ST400F features an upholstered seat and back that fit like a glove and provide a bit more cushioning support than the Office Master ST400. Easy to set up, stack up, and store away.
Features
Features
Specifications
Specifications
Downloads / Info
Downloads / Info
Warranty
Warranty
Shipping
Shipping
Each OM Seating product is built from scratch and requires time to be manufactured.
Lead time is typically up to 7-10 business days, however for a most updated production time estimate, please reach out to us via the chat or email at cs@estorescorp.com
Choosing the right arms is crucial for an optimal ergonomic setup. Use this guide to help you choose the best arms for your needs.
Pick Your Adjustability
- 1D — Height only
- 2D — Height & Width (best everyday choice)
- 3D — Height, Width + Pivot or Fore-Aft
- 4D/4D+ — Height, Width, Pivot & Fore-Aft
Measure Your Elbow Height
- Sit in your current chair with arms resting relaxed and elbows near 90°.
- Armrests should be level with your desk surface.
- Measure seat to top-of-armrest — that’s your needed range.
Find Your Match Below
Pick the required adjustability (Fixed, 1D, 2D, 3D, 4D) from Step 1, then use your elbow-height range from Step 2 to choose the right arms from the table below.
| Dimension | Arm Model | Type | Features | Min Height (approx. from seat pan) | Max Height (approx. from seat pan) |
|---|---|---|---|---|---|
| Fixed | KR48 | Average height | Fixed loop | 9.75" | 9.75" |
| 1D | BR2 | Average height | Width-only, loop design (BC only) | – | – |
| 1D | AR81 | Average height | Width-only, polished aluminum loop | 8.25" | 8.25" |
| 1D | JR77 | Average height | Height-only | 8.25" | 12.5" |
| 1D | JR77M | Average height | Height-only, Memosoft | 8.25" | 12.5" |
| 1D | JRBN | Tall height | Height-only, fold-back ballistic | 9.25" | 11.75" |
| 1D | JRPD | Tall height | Height-only, fold-back Memosoft (Police) | 9.25" | 11.75" |
| 1D | KR21 | Average height | Height-only, knob T-arm | 8.5" | 10.75" |
| 1D | KR23 | Short height | Height-only | 6.5" | 10" |
| 1D | KR25 | Average height | Height-only, natural grip | 8.25" | 11" |
| 1D | KR25M | Average height | Height-only, Memosoft natural grip | 8.25" | 11" |
| 2D | BR5 | Average height | Height + Width (BC only) | – | – |
| 2D | JR39 | Average height | Height + Width, forward slant | 7.25" | 11.5" |
| 2D | JR39M | Average height | Height + Width, forward slant, Memosoft | 7.25" | 11.5" |
| 2D | KR200 | Short height | Height + Width, removable T | 6.25" | 8.25" |
| 2D | KR200M | Short height | Height + Width, Memosoft removable T | 6.25" | 9" |
| 2D | KR100M | Short height | Height + Width, Memosoft removable T | 5.25" | 8" |
| 2D | KR300 | Tall height | Height + Width, tall T | 7.75" | 10.5" |
| 2D | KR300M | Tall height | Height + Width, tall Memosoft | 7.75" | 10.5" |
| 3D | AR485 | Average height | Height + Width + Pivot, polished aluminum | 7.0" | 11" |
| 4D | JR49 | Tall height | Height + Width + RP-45 pivot + Fore/Aft | 8.75" | 13" |
| 4D | JR59 | Tall height | Height + Width + RP-50 6-way Omni | 8.5" | 12.75" |
| 4D | JR69 | Tall height | Height + Width + RP-65 pivot/Fore-Aft | 8.25" | 12.5" |
| 4D | KR200-45 | Average height | Height + Width + RP-45 pivot/Fore-Aft | 7.75" | 10.5" |
| 4D | KR200-65 | Average height | Height + Width + RP-65 lockable top | 7" | 9.75" |
| 4D+ | KR200-50 | Average height | Height + Width + RP-50 Omni (4D+) | 7.75" | 10.5" |
| 4D | KR100-45 | Short height | Height + Width + RP-45 pivot/Fore-Aft | 6.75" | 9.5" |
| 4D | KR100-65 | Short height | Height + Width + RP-65 lockable top | 6" | 8.75" |
| 4D+ | KR100-50 | Short height | Height + Width + RP-50 Omni (4D+) | 6.75" | 9.5" |
| 4D+ | KR100-51M | Average height | Ultra mobility track arm, RP-51M, 360° pivot | 7.5" | 10.25" |
| 4D | KR300-45 | Tall height | Height + Width + RP-45 pivot/Fore-Aft | 9.25" | 12" |
| 4D | KR300-65 | Tall height | Height + Width + RP-65 lockable top | 8.5" | 11.25" |
| 4D+ | KR300-50 | Tall height | Height + Width + RP-50 Omni (4D+) | 9.25" | 12" |
| 4D | JR77-65 | Tall height | Height + Width + RP-65 pivot/Fore-Aft | 9.5" | 13.75" |
With over 200 fabrics and multiple fabric materials, we understand that choosing a fabric can be overwhelming. Use the guide and table below to get a better understanding of how to select the right fabric for you.
| Grade | Pattern | Type / Material | Codes | Cleanability | Abrasion |
|---|---|---|---|---|---|
| G1 | Basic | Woven | 1001–1020 | WS | 150,000+ |
| G1 | Spice | Woven | 1161–1168 | WS | 150,000+ |
| G1 | Celestial | Woven | 1200–1204 | WS | 150,000+ |
| G2 | Chess | Woven | 2293–2298 | WS | 100,000+ |
| G2 | Clue | Woven | 2400–2409 | W | 40,000+ |
| G2 | Drift | Woven | 2700–2709 | BC & WS | 100,000+ |
| G2 | Knack | Woven | 2542–2548 | WS | 100,000+ |
| G2 | SoftSit | Knit | 2570–2589 | WS | 100,000+ |
| G2 | Track | Woven | 2710–2714 | W | 40,000+ |
| G3 | Beau | Woven | 3800–3810 | BC & WS | 100,000+ |
| G3 | Bliss | Woven | 3900–3908 | W | 150,000+ |
| G3 | Cinema | PVC-Free | 3P30–3P40 | BC & WS | 150,000+ |
| G3 | Free | Woven | 3401–3406 | WS | 100,000+ |
| G3 | Illusion | Vinyl | 3V80–3V89 | BC & WS | 100,000+ |
| G3 | Line Up | Woven | 3501–3508 | WS | 100,000+ |
| G3 | Stage | Vinyl | W & BC | 150,000+ | |
| G3 | XOX | Woven | 3702–3709 | S | 80,000+ |
| G4 | Cover Cloth | Crypton | 4C00–4C08 | W & BC | 150,000+ |
| G4 | Hopsack | Vinyl | 4V10–4V19 | BC & WS | 100,000+ |
| G4 | Rocket | Woven | 4500–4507 | WS | 100,000+ |
| G5 | Architect | Knit | 5700–5709 | W | 150,000+ |
| G5 | Comfortknit Solids | Knit | 5501–5539 | W | 150,000+ |
| G5 | Myth | Knit | 5200–5208 | WS | 150,000+ |
| LG1 | Evita Leather | Leather | LBLK–LWHT | — | — |
| LG2 | Lena | Leather | LDEL–LORC | — | — |
| LG3 | Vulcano | Leather | LMIT, LSTG | — | — |
| - | Neighborhood | Mesh | 5300–5308 | WS | 80+ |
| - | Zodiac | Mesh | 2300–2310 | WS | 80+ |
The cylinder controls the seat height range of your chair. In the chart to the left, you can see how each cylinder changes the chair height compared to the standard 5" cylinder (shown as “standard” in the table).
The right caster depends on the type of floor you’ll be using your chair on.
The chart on the left shows which caster performs best across different surfaces - from soft carpet to hard concrete.
Every OM Seating chair is built with ergonomic mechanisms that let you fine-tune comfort and support throughout the day.
The image to the left highlights the specific mechanism on this model and shows the available adjustments.
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We’re proud to be an authorized reseller for OM Seating and Special-T, bringing you direct access to their high-quality products with the full support you deserve.
Frequently Asked Questions
Which fabric option should I choose?
Which fabric option should I choose?
Fabrics are grouped by Grade, and each grade contains different Patterns (these are essentially collections).
On the product page, you’ll first pick a Grade, then browse the full list of fabrics in that grade to select your exact fabric (e.g., 1200-Oberon).
- Grade – Grades (G1, G2, G3, etc.) are price tiers, with higher grades offering more premium styles and materials.
- Pattern – A style or collection within a Grade. Each pattern comes in a range of colors with the same design, and type (material).
- Type (Material) – The fabric material, such as woven, knit, vinyl, leather, mesh, etc.
For full details please refer to the Options Library Page.
Which arms options should I choose?
Which arms options should I choose?
Arm selection is mainly based on adjustability and fit (height from seat):
- Adjustability Levels – 1D (height or width only), 2D (height + width), 3D (height, width + pivot or fore-aft), 4D/4D+ (full range of height, width, pivot, and fore-aft).
- Measure Your Elbow Height – Sit comfortably with arms at 90°, then measure from the seat to the top of your elbow to find the correct arm range.
- Match Your Group – Combine your preferred adjustability (Fixed, 1D–4D) with your elbow height to find the best fit.
Refer to our Choosing Arms Guide above for the full list of arm options, grouped by adjustability.
Is there a warranty on this product?
Is there a warranty on this product?
How long will it take to ship?
How long will it take to ship?
All OM Seating chairs are manufactured upon order and typically ship within 7-10 business days. Replacement parts such as arms, cylinders, and casters, may ship out sooner.
Delivery times can vary based on your location. For the most accurate lead time, please reach out to us via chat or email at cs@estorescorp.com
Are there bulk discounts available?
Are there bulk discounts available?
Yes!
Bulk discounts are available for orders of 5 or more chairs. Discounts are tiered, meaning the more you purchase, the greater the savings. For example, smaller bulk orders may qualify for a modest percentage off, while larger orders receive a higher discount.
What is your return policy if the chair doesn’t work for me?
What is your return policy if the chair doesn’t work for me?
Chairs can be returned within 30 days in their original packaging and condition. Because each chair is custom-built, a restocking fee will apply. You’ll need an RMA (Return Merchandize Authorization) number before sending anything back. Full details are available on our Return Policy page, or you can email cs@estorescorp.com for assistance.