The Complete FIT Rife History & Device Compatibility Guide

FIT Rife has been engineering frequency delivery devices since 2012 — first sold under other companies' branding, and now sold directly under its own name. This guide covers the full story: how each device in the FIT line evolved, what those devices used to be called before the FIT Rife name existed, and — the question most people actually arrive here to answer — which accessories work with which device.

If you're looking for a quick summary instead, see our FIT Rife brand page. This article is the deep-dive version.

A Decade of Engineering Evolution

Each generation of the FIT line was built to solve a specific engineering problem: how to deliver frequency more precisely, more flexibly, and more reliably than the model before it.

FIT I — The Foundation (2012)

Conceptualised in 2012, the FIT I was the first device in the line and remains the simplest in concept: it was built around handheld electrodes, delivering frequency via voltage pulses through direct skin contact.

From the outset it was designed for compactness, lightness, and durability — a slightly recessed screen to protect against accidental damage, and a standard 18650 single-cell lithium-ion battery for reliable power management. Later production runs became more modular internally, simplifying manufacturing and repairs, while the external form factor stayed consistent across every iteration.

The FIT I is not designed to be used with a PEMF coil — the coil requires higher current and lower voltage than the FIT I's voltage-pulse design delivers, so pairing the two is not supported.

FIT II — A Different Approach (2021)

First prototyped in 2021, the FIT II took the opposite design path: it was engineered specifically for use with a PEMF coil, delivering frequency through current pulses rather than voltage pulses — a fundamentally different power delivery method suited to a different application.

Like the FIT I, it's compact and lightweight, with a recessed screen for durability and a modular internal build. Because its power delivery is current-based rather than voltage-based, the FIT II is not compatible with the handheld electrodes used by the FIT I.

FIT III — Bringing Both Together (2015)

Launched in 2015, the FIT III combined the full capabilities of the FIT I and FIT II into a single device, letting users choose handheld electrodes or a PEMF coil from one unit — one at a time, not simultaneously. The original model sold over 800 units before a 2021 redesign replaced its resistive screen and two brass jacks with a 4.3" capacitive touchscreen and four composite banana jacks — a major reliability upgrade that also improved the day-to-day interface. The original 2015 model was discontinued at that point, following the closure of key component suppliers.

Internally, the FIT III moved away from the modular architecture of the FIT I and FIT II toward a single, streamlined PCB — a design choice that carried through to the FIT IV as well. A USB-C charge port was added to the FIT III in July 2026.

FIT IV — Simultaneous Delivery (2021)

The FIT IV was engineered directly in response to customer demand for simultaneous therapies. Housed in the same enclosure as the FIT III and sharing its 18650 battery and singular PCB architecture, the FIT IV introduces multi-channel power routing: it can run a PEMF coil and a set of handheld electrodes at the same time, or two sets of handheld electrodes simultaneously — useful for multi-zone targeting or two-person use.

Version 1 (2021) used an external PEMF coil. Version 2, launching July 2026, integrates the PEMF coil directly into the device and adds a USB-C charge port.

Built to Last: What the FIT Line Has in Common

Every device in the FIT line runs on a standard 18650 lithium-ion battery and shares a durability-first design philosophy — from the FIT II's impact-protected recessed screen to the shared, reinforced enclosure of the FIT III and FIT IV. As the product line matured, internal architecture moved from modular components (FIT I and FIT II) toward a streamlined, singular PCB design (FIT III and FIT IV) — improving reliability without sacrificing serviceability.

The Manufacturer Brand: FIT Rife and the Wave Technologies Years

FIT Rife is the manufacturer behind the FIT series. For over a decade, that engineering was sold to customers under other companies' branding rather than the FIT Rife name — most notably through Wave Technologies, who distributed each FIT model under its own separate product name:

FIT Rife device	Sold by Wave Technologies as
FIT I	Wave Kompak
FIT II	Wave Pulse
FIT III	Wave 5 (Professional)
FIT IV	Wave 6 (Practitioner) — sold with an external PEMF coil, prior to the internal-coil FIT IV V2

That arrangement has ended. FIT Rife no longer sells through Wave Technologies or under any of those names — every device is now sold directly under the FIT Rife brand, representing the manufacturer that has designed and built this technology since 2012.

Something Natural is the official distributor of the FIT Rife range in South Africa.

FIT Rife Device & Bundle Compatibility Guide

Not every accessory works with every device — the table below covers what's included, what's optional, and what isn't compatible at all, across every FIT device and bundle.

FIT Rife Device & Bundle Compatibility

Device / Bundle	Handheld Electrode Set	PEMF Coil Mat	PEMF Coil Waistpad	Formerly sold as
FIT I	✓ Included	✗ Not compatible	✗ Not compatible	Wave Kompak
FIT II	✗ Not compatible	● Optional (one at a time)	● Optional (one at a time)	Wave Pulse
FIT II & Mat Bundle	✗ Not compatible	✓ Included (one at a time)	● Optional (one at a time)	Wave Pulse
FIT II & Waistpad Bundle	✗ Not compatible	● Optional (one at a time)	✓ Included (one at a time)	Wave Pulse
FIT III	✓ Included (one at a time)	● Optional (one at a time)	✗ Not compatible	Wave 5 (Professional)
FIT III & Mat Bundle	✓ Included (one at a time)	✓ Included (one at a time)	✗ Not compatible	Wave 5 (Professional)
FIT IV (internal PEMF coil)	✓ Included (simultaneous)	● Optional (simultaneous)	✗ Not compatible	Wave 6 (Practitioner) — external PEMF coil only
FIT IV & Mat Bundle (internal PEMF coil)	✓ Included (simultaneous)	✓ Included (simultaneous)	✗ Not compatible	Wave 6 (Practitioner) — external PEMF coil only

Reading the table: Included means the accessory comes standard with that device or bundle. Optional means it's compatible but sold separately, and where noted, can only run one accessory at a time rather than simultaneously. Not compatible means the accessory does not work with that device at all, regardless of what's bundled.

A spare or replacement Electrode Cable Set is also available — it uses a 4 mm connector and is not compatible with FIT I, which uses a different connector type.

Frequently Asked Questions

Is the FIT I the same as the Wave Kompak? Yes. The FIT I is the same device that was previously sold by Wave Technologies under the names Wave 4, Wave Pulse, and Wave Kompak. It's now sold only under the FIT Rife name.

Can I use my old Wave accessories with a new FIT Rife device? It depends on the accessory and which Wave model your device corresponds to. Handheld electrodes and PEMF coils are not interchangeable between the voltage-pulse devices (FIT I) and the current-pulse devices (FIT II), and the Electrode Cable Set specifically is not compatible with FIT I. See the compatibility table above for a full breakdown.

What happened to Wave Technologies? Wave Technologies previously distributed the FIT Rife devices under its own branding. That arrangement has ended, and FIT Rife devices are now sold directly under the FIT Rife name rather than through Wave Technologies.

Which FIT Rife device should I choose? If you only need handheld electrodes, the FIT I is the simplest option. If you specifically want PEMF coil therapy, the FIT II is purpose-built for it. If you want the flexibility to switch between electrodes and a PEMF coil, the FIT III covers both (one at a time). If you want to run electrodes and a PEMF coil simultaneously — or two sets of electrodes at once — the FIT IV is the only device in the range built for that.

Can the FIT III or FIT IV run electrodes and the PEMF coil at the same time? The FIT III can use either accessory, but only one at a time. The FIT IV is the only device in the range that can run a PEMF coil and handheld electrodes simultaneously.

Does the PEMF Coil Waistpad work with FIT III or FIT IV? No — the PEMF Coil Waistpad is only compatible with the FIT II.

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Something Natural is the official distributor of the FIT Rife range in South Africa. Browse the full FIT Rife range or see individual product pages for pricing and availability.