Product · ProtoArc
ProtoArc EC300: 6 cm back height, 5 cm seat slide
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ProtoArc's EC300 tackles a common problem for tall people: the lumbar curve and headrest of a standard chair sit too low. Instead of moving just a lumbar pad, the whole backrest slides up by 6 cm, carrying the lumbar zone and headrest together. ProtoArc pitches it at users from 163 to 195 cm, the highest upper figure among the ergonomic chairs here, making it a strong contender for lanky users who are not especially heavy.
- Seat depth
- 5 cm, 5 positions
- Lumbar
- Fixed, moves with 6 cm back
- Armrests
- 7 cm height, flip-up
- Tilt
- Synchro, 4 positions to 130°
- Max load
- 127 kg
In its favour
- Raising the whole backrest by 6 cm moves the lumbar area and headrest together, which helps line the back up with your spine.
- The seat slides through 5 lockable positions over 5 cm, and the maker quotes a fit range of 163 to 195 cm in height.
- ProtoArc states the chair meets BS EN 1335 and uses a TUV Rheinland certified class 4 gas lift.
Good to know
- The lumbar is described as firm and fixed to the backrest, so you cannot set its depth separately.
- The 127 kg load rating is lower than several rivals here, which rules it out for heavier users.
Our take
Back, lumbar and headrest
The backrest uses a nylon frame and rises 6 cm in total. Lumbar support is firm and built into the back, covering both the lumbar spine and sacrum with a wide pad. There is no separate depth setting, so you cannot push it further into your back or pull it away; it moves only with the backrest.
The 3D headrest adjusts up and down, forward and back, and rotates on two axes, letting you angle the pillow independently of the frame.
Seat and recline
The seat slides through five lockable positions over 5 cm, which is how the chair covers such a wide height range. It is made from 55D moulded foam under a breathable mesh top, and ProtoArc reports 100,000 impact tests without flattening. Amazon gives the seat depth as 50 cm.
A synchronous tilt mechanism locks at four positions up to 130 degrees. The armrests are 11 cm wide, rise 7 cm and flip up.
Certification, load and warranty
ProtoArc states BS EN 1335 compliance, SGS testing to ANSI/BIFMA X5.1 and a TUV Rheinland certified class 4 gas lift. The bullets quote a 127 kg maximum load, while the spec table lists 220 lb, around 100 kg, so heavier buyers should confirm the true limit. A 5-year warranty with free replacement parts is included, and assembly is quoted at around 20 minutes.
How it compares
The Hinomi H2 Pro offers adaptive lumbar with depth control, a deeper recline and a 150 kg rating, though Hinomi does not publish a user height range. ProtoArc's own EC200 is a cheaper sibling with a seat depth range of 33 to 43 cm and a 2-way lumbar. The EC300 is the pick when back height, not lumbar depth, is your issue.
Verdict
The EC300 suits tall, lighter users who need the lumbar and headrest raised as one unit. If you want separate lumbar depth control or a higher weight rating, the Hinomi H2 Pro is the better match, and users of average height on a tighter budget may be well served by the ProtoArc EC200.
Compared with alternatives in: Best ergonomic office chairs for a home office, Best Herman Miller alternatives, Best office chairs for tall people
Amazon listing title: ProtoArc EC300 Ergonomic Office Chair with Height Adjustable Backrest