Deepshark Bed Gap Filler for King Mattress - High-Density 45D Foam

Our review of the Deepshark Bed Gap Filler for King Mattress finds it best for sleepers who need a simple, durable solution to the annoying gap between mattress and headboard or wall. The single biggest reason to buy is the high-density 45D sponge core combined with a removable linen cover, which provides firm support to stop pillows, remotes and pets from falling into the crack while remaining easy to clean. For anyone wanting a cleaner, wider sleeping surface without replacing bedding, this is a practical fix.

Key Features

• Multiple size options: Available to fit common mattress widths including 39 in, 54 in, 60 in and 78 in so you can choose a precise length for Twin through King sizes.
• High-density 45D sponge: The core is resilient and firm, designed to maintain shape and prevent collapse under pillows and light pressure.
• Removable linen cover: A breathable, skin-friendly linen fabric with a durable zipper makes the cover easy to remove and wash for routine cleaning.
• Wide application range: Intended for the gap at the headboard, between two mattresses, or against a wall, it effectively fills variable bed cracks.
• Expandable packaging: The sponge ships compressed and regains full size within 48-72 hours, allowing compact shipping without long-term performance loss.

Who It's For

The Deepshark gap filler is for anyone with a visible gap at the head of the bed who wants a quick, non-permanent fix that keeps pillows and small items from falling. It suits households that value a firmer filler and want a cover that can be removed and laundered.

Those who should look elsewhere include buyers who need a very soft or plush wedge rather than a firm foam, or shoppers who cannot wait for the compressed foam to fully expand, as some customers report incomplete expansion over the first days.

Pros & Cons

Pros

• Firm, high-density foam that reliably fills headboard gaps and keeps items on the mattress.
• Wide range of sizes so the filler can match mattress width from Twin through King.
• Breathable linen cover with zipper makes cleaning straightforward and keeps the unit hygienic.

Cons

• Compression packaging means the foam can take 48-72 hours to expand fully and some users report incomplete expansion.

Specifications

Brand	DEEPSHARK
Core material	High-density 45D sponge
Cover material	Breathable linen fabric, removable with zipper
Available sizes	39 in, 54 in, 60 in, 78 in (Twin to King)
Applications	Headboard gap, between two mattresses, mattress to wall
Care	Cover removable; tumble dry low or air dry

Our Verdict

The Deepshark Bed Gap Filler is a straightforward, good-value solution for filling mattress-to-headboard gaps, especially for users who want firm support and an easy-to-clean cover. It is best for those prepared to allow time for the compressed 45D sponge to expand; despite that, the build quality and size options make it a practical addition to most bedrooms.

Frequently Asked Questions

Will the filler fit my King mattress?
The product is available in a 78 in option intended for King mattresses and other sizes for Twin, Full and Queen widths.

Can I wash the cover?
Yes, the linen cover has a zipper and is removable; the manufacturer recommends tumble dry low or air dry.

How long until the foam expands?
The compressed sponge typically needs 48-72 hours to fully expand after unpacking, though some customers report a longer or incomplete expansion period.