Microcoils, support coils and triple-stranded springs: what each does

First identify how the springs connect

Regular coils is an imprecise description. A USITC manufacturing report distinguishes four common constructions: (Coil construction report)

• Bonnell: hourglass-shaped springs joined in rows by spiral connecting wires.
• Offset: linked springs with flattened portions that allow a hinging action.
• Continuous wire: shaped wire runs through rows of coils, with connecting wires holding the assembly together.
• Pocketed: separate fabric cases surround individual springs; the cases are connected to neighboring cases.

(Coil construction report)

Pocketed springs are still innersprings. Individual fabric pockets do not mean the finished mattress consists of unconnected parts. (Coil construction report)

A comfort layer is different from the main core

Spinks' patent describes springs wider than their pocketed height. Figure 10 combines that layer with a conventional pocketed or open-coil unit. Small springs can supplement the main core. (Spinks layer patent)

Spinks' Micro range lists varied pocket heights and Comfort, Support and Ultra Firm versions. It offers these spring layers as alternatives to foam and other fillings. (Spinks Micro range)

The word micro does not define a universal height cutoff. Leggett & Platt uses Micro and Super Micro for narrow-diameter pocketed innersprings. Ask for the actual height, diameter and position in the mattress; a small diameter and a shallow layer describe different dimensions. (Micro diameter details)

Triple-stranded describes the wire within a spring

Beautyrest's 2019 release describes T3 Pocketed Coil construction as three steel strands woven into one coil. Think of the strands forming the spring's wire, rather than three complete springs stacked on one another. That construction alone is not a measurement of firmness or a promise of three times the support. (Beautyrest 2019 release)

Beautyrest now uses the name Triple-Stranded Pocketed Coil and lists it alongside 4K Micro Coils in its Series Five XCS Plush model. The features coexist. If a description says triple-banded, ask which technology it means; the verified Beautyrest term used here is triple-stranded. (Current XCS construction)

Why one number cannot predict the feel

A Dreamwell stranded-spring patent identifies wire thickness, coil diameter, unloaded length and active turns as design variables. Active turns are the portions that deform under load. It describes variable responses to loading in both solid-wire and stranded designs. Consequently, matching one specification, such as wire thickness, does not establish that two springs respond identically. (Stranded spring patent)

Spinks bases its coil counts on a 150-by-200-centimeter size. Compare counts after identifying the size and whether each figure describes the core, an added layer or their combined total. (Spinks Micro range)

Documented milestones are not all invention dates

James Marshall's US patent, filed in September 1900 and granted October 22, 1901, describes springs enclosed in fabric pockets stitched into strips. It documents an early pocket-spring design, not a verified first retail sale. (Marshall patent)

Harrison Spinks dates its low-height Posturfil development to 2003 in its company history. That is an attributed development milestone, rather than proof of a worldwide first. (Spinks company history)

The Spinks layered-unit patent application was published September 15, 2005. Publication records a disclosed design; it does not date the first mattress sold with it. (Spinks layer patent)

Richard F. Gladney's Dreamwell stranded-spring patent was granted September 20, 2005. That date does not establish when today's branded Beautyrest system launched. (Stranded spring patent)

Beautyrest's January 2019 announcement documents a new Black collection featuring T3. It is a collection-introduction record, not an assertion that the underlying technology was invented that year. (Beautyrest 2019 release)

Choose the complete design for your priorities

Consider microcoils when you want to compare spring-based cushioning; select the specified feel rather than assuming small means soft.

For a shared bed, compare the movement you actually notice when each person turns. For someone who dislikes sinking deeply, compare how easy it feels to roll over. Those observations can make one finished mattress preferable to another, but they do not isolate the contribution of one coil system.

These sources describe construction, not independent finished-mattress trials. Coil names alone do not establish comfort, cooling or durability.