ProtoArc SC Butterfly Ergonomic Memory Foam Seat Cushion

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Product guide

ProtoArc SC Butterfly Ergonomic Memory Foam Seat Cushion

Ergonomic: The ProtoArc SC Butterfly is a memory foam seat cushion with a U-shaped cut-out intended to reduce concentrated pressure during sitting. A carry handle and removable cover make it easier to move and maintain, but the listing gives inconsistent thickness and size details that are worth checking before purchase.

At a glance

U-shaped cut-out and split cushion design are claimed to distribute pressure across the hips and thighs.
Memory foam is described as pre-shaped, medium firmness and infused with bamboo charcoal.
Removable zip cover, non-slip base and built-in carry handle are listed.
The listing recommends the cushion for people weighing less than 200 pounds.

Price

£22.79Save 24%

Reference price: ~~£29.99~~

Price checked: 14 Nov 2026

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Pros and cons

Pros

The U-shaped opening and split design offer a targeted alternative to a flat seat pad for buyers seeking coccyx-area support.
A handle and removable cover add practical portability and cleaning convenience, according to the listing.
Customer feedback reports comfort and support during longer sitting sessions.

Cons

Customer feedback includes reports of the cushion shifting, feeling too small, or flattening over time.

Technical specifications

15 specifications

Identity
Brand	ProtoArc
Model	SC Butterfly
Type	Furniture Cushion
Size	L
Colour	Dark Gray

Dimensions and installation
Dimensions	45.7L x 40.6W centimetres
Weight listed	1.09 Kilograms
Thickness listed	4.3 Inches
Shape	Semicircular

Materials and care
Material listed	Wool Cloth
Fill	Memory Foam, ideal for < 200 lbs
Care instructions	Dry Clean Only, Machine Wash

Use
Firmness	Medium
Recommended uses	Driving, Reading, Resting, Sitting, Studying, Traveling, Working
Indoor or outdoor	Indoor

What to know before buying

The listing says the vacuum-sealed cushion needs one or two hours to expand and that adjusting to its shape may take one to two weeks.

Listing details to confirm

Listing details are inconsistent: one feature gives an 18"L x 16"W x 4"H size and 4.0" thickness, while the technical details list 45.7L x 40.6W centimetres and 4.3 Inches. The cover is described as both wool and machine-washable, while care details also say dry clean only. Confirm the selected listing’s dimensions, thickness and cover-care instructions. The weight guidance says less than 200 lbs and recommends the SC Butterfly XL above 100kg, so check suitability if near or over those limits.

Who is it for?

A good fit for

People wanting a portable seat cushion for an office chair, car seat or other listed sitting uses.
Buyers looking for a U-shaped memory foam cushion and removable cover.

Less suited to

People who need confirmed dimensions or a clearly specified cleaning method without checking the listing first.
Buyers above the stated weight guidance who do not want to consider the recommended XL version.

ProtoArc SC Butterfly Ergonomic Memory Foam Seat Cushion · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.3 / 5 · 2,577 ratings

5 stars69%69%
4 stars11%11%
3 stars10%10%
2 stars6%6%
1 star4%4%

Customer feedback highlights comfort, cushioning and perceived pressure relief during longer sitting, with customers also describing the support as helpful. This aligns with the listed memory foam and U-shaped cut-out, but it does not establish a particular medical outcome. Experiences with grip and size vary, and some feedback reports that the foam may flatten over time. Those concerns matter if you need a consistently fixed fit or long-term firmness.

Positive themes

Customers report comfortable cushioning and support for longer sitting.
Customer feedback describes perceived pressure relief and appreciates the U-shaped support.

Mixed feedback

Feedback is mixed on grip, with some customers saying it stays in place and others reporting movement.
Customers differ on size, and some report that the foam flattens over time.

Frequently asked questions

What shape is the ProtoArc SC Butterfly cushion?

The listing describes a U-shaped cut-out and a semicircular item shape. It says the design is intended to help distribute pressure.

What are its dimensions and thickness?

The details list 45.7L x 40.6W centimetres and 4.3 Inches thick. A feature description instead gives 18"L x 16"W x 4"H and 4.0" thickness, so confirm the selected listing before buying.

Can the cover be machine-washed?

The feature text says the removable zip cover is machine-washable, but the care details say both dry clean only and machine wash. Check the care instructions for the selected item.

How long should it expand before use?

The listing says to allow one or two hours for the vacuum-sealed cushion to expand. It also notes that adjusting to the cushion’s shape may take one to two weeks.