Pillowflex Premium Polyester Throw Pillow Insert 21x37 - Ultra Soft

In this review of the Pillowflex Premium Polyester Throw Pillow Insert 21x37, the bottom line is simple: it is a soft, machine-washable insert made to give decorative shams a full, smooth look. The insert is aimed at anyone who wants crisp corners and a plump appearance for 20x36 or 21x37 shams, and the single biggest reason to buy is the combination of a silicon-treated virgin fiber fill and a high thread count shell that resists lumping and arrives ready to use.

Key Features

• Correct sizing: The 21x37 insert is sized to fill 20x36 and 21x37 shams so covers look properly full without sagging or underfilling.
• Soft but full fill: Virgin 7 denier polyester fiber gives a soft hand while keeping a plump shape that supports corners and maintains loft.
• Silicon-treated fiber: The treated fill resists clumping so shams stay smooth and require less fluffing after unpacking or washing.
• Machine washable: The shell and fill are washable with a safety stitch to prevent unraveling, making care practical for everyday use.
• Hypoallergenic construction: Made from odorless American polyester fiber that is lint and dust free and contains no flame retardant chemicals.
• Made in USA: Manufactured in Palmetto, GA from sustainably sourced materials, supporting domestic production.

Who It's For

This insert suits homeowners and decorators who want a soft, full look for rectangular shams on couches, sofas, daybeds, and beds; it is also a good pick for anyone looking for a washable, hypoallergenic option for living spaces used daily. It performs well for those who prefer a slightly softer, plush feel rather than a very firm lumbar support.

Shoppers who need a removable, zippered cover or a very firm orthopedic lumbar support should look elsewhere, because the Pillowflex shell is not removable and the loft is described as medium-soft rather than extra-firm.

Pros & Cons

Pros

• Soft, smooth feel that fills covers and makes shams look more expensive and polished.
• Silicon-treated fiber resists lumping, so the pillow stays even and requires less maintenance.
• Machine washable and hypoallergenic, suitable for regular household use and easy care.
• Made in USA with a high thread count shell and safety stitch for durability when washed.

Cons

• Shell is not removable, which may be a drawback for users who prefer separate covers for washing or replacement.
• Not intended as a very firm lumbar support; those needing firm medical support should consider a different insert.

Specifications

Size	21x37 in (recommended for 20x36 or 21x37 shams)
Fill	100% virgin polyester fiber, 7 denier, silicon-treated
Shell	High thread count sewn shell, not removable, safety stitch
Care	Machine washable
Allergens	Hypoallergenic, odorless, lint and dust free
Origin	Made in USA (Palmetto, GA)

Our Verdict

The Pillowflex 21x37 polyester insert is a solid choice for anyone wanting a soft, plump look for rectangular decorative shams without the hassle of frequent fluffing; its silicon-treated fill and washable high-thread-count shell make it good value for home decorators and everyday sofas. Buy it if you want smooth corners and a cozy feel; choose a removable or firmer insert if you need specialized support or separate covers.

Frequently Asked Questions

Will this insert fill a 20x36 sham?
Yes, the 21x37 insert is recommended for use in 20x36 and 21x37 shams to achieve a full look.

Can I wash this pillow in a home machine?
Yes, the insert is machine washable and features a safety stitch to help the shell remain intact during washing.

Is the fill hypoallergenic?
Yes, the pillow uses American-made polyester fiber that is hypoallergenic, odorless, and lint and dust free.