WhatsBedding FTHM-BBDP King 4-Inch Memory Foam Mattress Topper

The WhatsBedding FTHM-BBDP memory foam mattress topper is listed in King size at 4 inches thick, with a plush feel and a deep-pocket fitted skirt. Its bamboo-viscose and polyester cover and slow-rebound foam are intended to add soft cushioning over an existing mattress.

At a glance

The listing specifies a 4-inch King topper with a plush feel and slow-rebound memory-foam fill.
The elastic skirt is stated to fit mattresses 8–21 inches deep, and quilting is intended to help keep fill in place.
The listing describes the cover as a breathable bamboo-viscose and polyester air-layer fabric.

Price

$75.99Save 48%

Reference price: ~~$145.99~~

Price checked: Nov 14, 2026

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Pros and cons

Pros

The deep-pocket fitted skirt is specified for a broad mattress-depth range of 8–21 inches.
A 4-inch plush foam layer offers substantial cushioning for buyers seeking a softer feel over a firm mattress.
The maker says the quilted construction helps limit fill shifting and clumping.

Cons

The maker says this soft, fluffy topper cannot replace a mattress, so it is not a substitute for a worn-out or unsuitable mattress.
The topper is not listed as water resistant, and the care guidance cautions against washing the entire topper.

Technical specifications

12 specifications

Identity and size
Brand	WhatsBedding
Model	FTHM-BBDP
Size and thickness	King (4 in)
Color	Bamboo Green

Materials and protection
Cover fabric	39% Bamboo Viscose Air Layer, 61% Polyester
Water resistance listed	Not Water Resistant
Fill material	Memory Foam

Feel and features
Firmness	Plush
Special features	Bagged, Breathable, Fluffy, Pillow Top, Skin-friendly
Closure type	Pull On

Fit and care
Listed mattress depth range	8-21 inches
Care instructions	Gentle Mode Machine Wash on Low, Spot Clean Only

What to know before buying

Listing details to confirm

Listing details are inconsistent about care and expansion: the specification says gentle low-mode machine wash, while product guidance says not to machine wash the whole topper and recommends spot cleaning. Expansion guidance varies between 24 hours and 24–48 hours. Confirm care instructions for the selected item, allow up to 48 hours to expand, and air it in a ventilated place if there is a new-foam smell.

Who is it for?

A good fit for

King-bed shoppers who want a plush, 4-inch cushioning layer over a firm mattress.
Buyers whose mattress is 8–21 inches deep and who want a fitted-skirt style topper.

Less suited to

Shoppers seeking a firm topper, a water-resistant surface, or a replacement for their mattress.
Anyone who needs clear, consistent instructions for machine washing the entire topper.

WhatsBedding FTHM-BBDP King 4-Inch Memory Foam Mattress Topper · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.5 / 5 · 452 ratings

5 stars75%75%
4 stars11%11%
3 stars9%9%
2 stars3%3%
1 star2%2%

Customer feedback reports positive impressions of comfort, softness, fit, thickness and perceived value, with some customers describing better sleep or less back and hip discomfort. These are customer-reported experiences, not a guaranteed result. The feedback's mention of a 5-inch depth conflicts with this listing's 4-inch King specification, so buyers should confirm the selected size and thickness.

Positive themes

Customers report comfort, softness, snug fit and added cushioning.
Customers describe improved sleep and relief from back or hip discomfort.

Frequently asked questions

What size and thickness is this topper?

The listing identifies it as King size and 4 inches thick.

What mattress depths can the skirt fit?

The listing states a fit range of 8–21 inches. Measure your mattress depth to check compatibility.

Can the entire topper be machine washed?

The care information conflicts. The specifications mention gentle machine washing on low, but the product guidance says not to machine wash the whole topper and recommends spot cleaning. Confirm the directions for the selected listing before washing.

How long should it expand after unpacking?

The guidance gives differing estimates of 24 hours and 24–48 hours. Allow up to 48 hours for expansion.