KYAKO Large Triangle Cushion High Rebound Triangular Pillow Inclined Mat for Nursing Beds

As shown in the photos, this was purchased just this month and is in new, unopened condition.
I bought it to use my desk PC while lying down, not for general use. However, I found that my body and the thickness of my mattress made the desk too low and it hit me, so I've decided to sell it.
This is not a cheap mat; I purchased one that is more solidly constructed than typical ones.

Below is a reproduction from the product page.

Brand: kyako
Color: Gray
Size: L65*W55*H19 (CM)
Filling material: 100% Urethane
Use: Both legs, back
Product firmness: Slightly firm
[Product Details] Usable size: (approx.) 55 x 65 x height 19cm | Packaged size: (approx.) W18 x D18 x H37cm | Weight: (approx.) 1,100g | Cover material: 100% Polyester | Filling: 25D high-resilience urethane
[Larger Size Than Market Products] Based on customer feedback, we have increased the size from the typical 50cm x 60cm to 55cm x 65cm. While maintaining ease of portability and storage, it now accommodates a wider range of body types and heights.
[Slightly Firm 25D High-Resilience] While a soft pillow might feel comfortable at first, for all-night use, a slightly firmer one provides better body fit. This is a masterpiece crafted by artisans from a long-established urethane specialist with 26 years of experience, offering solid support and durability. You'll appreciate its quality the more you use it.
[Just Right 16°] If the angle is too low, it's ineffective, and if it's too steep, it interferes with sleep. After repeated research and experimentation, we have finally settled on this gentle 16-degree angle. It achieves an effective angle while minimizing pressure on the tailbone and pelvis due to the incline, striking an appropriate balance between effectiveness and comfort.
[Velvet Cover You'll Want to Keep Touching] The smooth texture of the velvet cover is captivating and makes you want to keep touching it. With a U-shaped zipper, the cover is easy to remove, allowing you to maintain cleanliness even with long-term use.