A, B, C and D Beauty Machine Modes: What the Letters Cannot Tell You
Beauty Device Guides · Device literacy
A letter on a touchscreen is only useful when it can be traced to the correct device, accessory and instructions.
Short answer: A, B, C and D beauty machine modes do not, by themselves, tell you the pulse pattern, energy output, treatment order or safest starting point. Their meaning must come from documentation for the exact model and accessory. Without that match, do not assign A to continuous output, rank the letters by strength, or treat C/D as beginner settings. A mode label also cannot establish clinical benefit or suitability for a particular person. [1] [2]
What do A, B, C and D actually mean?
The defensible answer is the definition in the matching instructions for use (IFU). A screen showing four options is not enough to determine what changes between them. Until the manufacturer explains the mapping, whether a letter selects an output pattern, an accessory function or another setting remains unresolved.
FDA guidance for powered muscle stimulators calls for mode-specific output information, control descriptions and accessory details. It illustrates the need for documentation; it does not define a universal A–D system for beauty machines. [1]
For SQ16 and SQ16B: A current manufacturer IFU matched to the exact console and accessory was not verified for this article. No letter-to-waveform mapping, pause hierarchy or equivalence between those model names is established here. An explanation for a similar-looking machine cannot fill that gap.
There is therefore no supported universal instruction to use A first, move through B and C, then finish with D. Nor does a later letter establish a gentler setting. Those are operating claims that need device-specific documentation.
A mode is not an intensity level or a measured dose
Keep three questions separate: what function is selected, what the control changes, and what the device actually delivers. A percentage or numbered level is a control indication. Without its output mapping, it cannot be read as a calibrated exposure or compared directly with the same number on another console.
A technical description should connect the selected function to output measurements. For electrical stimulation, that includes waveform, pulse parameters and load-dependent voltage/current. [1]
A useful manufacturer example is the Ulthera system described in the Ultherapy PRIME US IFU retrieved for this article. It separates imaging from therapy and states that image-brightness controls do not affect output. The lesson is to read the defined function of a control rather than assume that a brighter display means more treatment energy. This example applies to that named system, not to SQ16/SQ16B or generic cavitation consoles. [3]
A stronger sensation is not an outcome measurement
Tingling, warmth or visible contraction does not establish a letter's clinical superiority. A contraction is not a measurement of fat thickness or bodyweight. Likewise, a circumference measurement cannot be substituted for either endpoint. FDA distinguishes non-invasive body contouring from weight loss; its consumer information on electronic muscle stimulators also cautions against unsupported body-shaping promises. [4] [5]
The same letters do not make different technologies equivalent
Use the same questions for every accessory: which function is selected, what output is documented, and which uses and results are actually supported? The table compares documentation needs, not treatment performance.
| Technology | Output and function to verify | Boundary to preserve |
|---|---|---|
| Ultrasound | Transducer identity, acoustic output and field, plus the purpose of each mode. [2] | Imaging, focused treatment and nonfocused cosmetic use are not interchangeable. A letter does not identify a target depth. [3] |
| Electrode stimulation | Intended use, waveform, pulse parameters, load-dependent output and approved electrodes. [1] | Do not equate EMS, TENS, microcurrent or DDS labels. Keep electrode systems separate from magnetic systems such as HIFEM. [1] [4] |
| External light | Emitter type, spectrum, output and whether the documented exposure is thermal or low-level. | External low-level light, heat-based laser treatment and invasive laser procedures need separate evidence. Visible red light cannot resolve device identity. [4] |
| Radiofrequency (RF) | Accessory and electrode configuration, output controls and thermal safeguards. | Surface RF and needle RF require separate documentation. The FDA's RF microneedling warning concerns needle-based procedures. [4] [6] |
A multifunction console still needs a map for each accessory. Do not assume that choosing a letter activates every advertised technology, or that functions operate simultaneously. Request an explicit mode-to-accessory-to-output description. FDA's focused-ultrasound guidance similarly emphasizes identifying system components, software and accessories. [2]
What to check in a matching manual
Before relying on an A–D explanation, collect a small, traceable documentation set:
- Device identity: manufacturer, exact model and the manual's applicable version or revision. Keep the console label and supplied documentation together.
- Accessory identity: the named handpiece, electrode, pad or transducer, including its part number where available.
- Mode definition: what each letter changes, which controls remain independent, and which outputs are enabled.
- Use boundaries: intended operator, permitted sites, contraindications, required protective measures and approved contact materials.
- Fault and stop instructions: what the indicators mean, how abnormal operation is handled, and when service is required.
This is a documentation checklist, not a treatment sequence. Record missing pulse information rather than estimate it from an illustration. FDA's reporting guidance calls for labeled waveform axes and test conditions. [1]
For trainers and customer service teams, keep the supporting page or section alongside any mode explanation. A record that says only “Mode C used” does not explain the accessory, other settings or intended function. If instructions conflict, obtain a written clarification for the exact device instead of combining fragments into a new protocol.
Safety cannot be assigned to a letter
Do not select a supposedly gentle mode to work around a contraindication or unclear instructions. Unknown output remains unknown at a lower screen setting.
For powered muscle stimulators, FDA guidance identifies a cardiac demand pacemaker contraindication and warns against stimulation across the chest or over the neck or mouth. It also notes that pregnancy safety has not been established and reports electrode-site irritation and burns. These are electrical-stimulation warnings within that guidance's scope, not a complete safety list for every beauty accessory. [1]
Body-contouring risks vary by technology; FDA describes burns and other injuries for relevant heat and ultrasound procedures. Suitability needs the exact device instructions and qualified assessment, especially where implants, skin damage or relevant medical conditions are involved. [4]
RF microneedling needs a separate boundary: the FDA's October 2025 safety communication reports serious complications with certain uses and advises against home use. It does not supply an adverse-event rate for ordinary surface RF. [6]
If burning, unexpected pain, skin injury or abnormal device behavior occurs, stop use and follow the device's fault instructions. Seek healthcare assessment for injury or persistent symptoms rather than trying another letter. FDA's EMS consumer page documents injuries and implant interference; the Ulthera IFU instructs users to discontinue use for unusual or inconsistent behavior. [5] [3]
Read the documented function behind the letter
A, B, C and D become meaningful only when the exact device documentation connects them to a defined function and output. Without that connection, leave timing, intensity rankings, beginner advice and treatment order unresolved. The useful next step is to obtain the matching instructions and accessory map.
Sources
- FDA: Guidance Document for Powered Muscle Stimulator 510(k)s — technical and labeling guidance, June 9, 1999; not a generic salon protocol.
- FDA: Focused Ultrasound Stimulator System for Aesthetic Use — guidance for the specified focused-ultrasound device category.
- Ultherapy PRIME: US Instructions for Use — retrieved document 1016413, Rev 00; a named-system documentation example.
- FDA: Non-Invasive Body Contouring Technologies — technology distinctions, outcome limits and risks.
- FDA: Electronic Muscle Stimulators — consumer information on claims and reported injuries.
- FDA: Potential Risks with Certain Uses of RF Microneedling — safety communication issued October 15, 2025.
Sources checked October 9, 2026. These documents do not establish the mode mapping, clinical performance or regulatory status of SQ16/SQ16B.
This article is for general educational purposes and does not provide medical advice. Follow the instructions for the specific device and consult a qualified healthcare professional about suitability and safety.