Arch4 is a London cashmere label founded in 2017 by Lynn Wei after more than a decade in knitwear design. It focuses almost exclusively on baby goat cashmere — fibre gathered once from kids in their first year, specified at 13.5 microns — sourced and knitted at a partner mill in Inner Mongolia. Sweaters run about £295–695.
Key facts
- Founded 2017 in London by Lynn Wei
- Works almost exclusively in baby goat cashmere, gathered once from kids in their first year
- Fibre is specified at 13.5 microns; yield is around 30 g per animal
- Designed in London and produced at a partner mill in Inner Mongolia
Fibres and construction
Arch4 works principally in Cashmere. Construction and techniques associated with the house include fully-fashioned. It is based in England, whose contribution to luxury knitwear is the fine-gauge knit: extra-fine merino and Sea Island cotton knitted at 24–30 gauge in Derbyshire and the Midlands, a tradition that began with the stocking frame in the 16th century..
How to judge Arch4 quality
- For cashmere pieces, look for a stated micron count or grade, 2-ply yarn for sweaters, and a dense knit with no daylight through plain areas. See the cashmere grading guide.
- This house knits fully-fashioned: check for fashioning marks along the armhole and flat, linked seams inside — the signatures of shaped, stitch-by-stitch construction.
Similar houses
Arch4: frequently asked questions
Where is Arch4 knitwear made?
Arch4 is based in London, England. Founded 2017 in London by Lynn Wei.
What is Arch4 known for?
Arch4 is known for traceable 13.5-micron baby cashmere designed in London and knitted in Inner Mongolia. Its principal fibres are Cashmere.
Is Arch4 a luxury brand?
Arch4 sits in the luxury tier of this index (roughly $400–$1,000 for a sweater). Its construction methods include fully-fashioned. It is listed here on the basis of fibre quality, construction and provenance rather than price alone.
How much does Arch4 knitwear cost?
Arch4 is roughly $400–$1,000 for a sweater at the time of writing. Prices vary by fibre and style.
Sources
Facts verified against the sources above on 16 September 2026. Prices are indicative and change; check the house's own site.