Sonic Electric Toothbrush (OEM / White Label)

Motor type and performance: linear resonance vs. magnetic levitation

Most factory spec sheets quote stroke frequency in the 31,000–40,000 strokes/min range, but the underlying motor technology determines actual cleaning performance more than the headline number.

Linear resonance actuator (LRA) motors are the dominant design in mid-range OEM toothbrushes. The bristle head oscillates along a single axis driven by a spring-mass resonant system. At resonance frequency, the LRA is highly efficient — but deviate from that resonant point and efficiency drops sharply. Well-designed LRA units hold frequency within ±2% under brush-head load; cheap designs drift noticeably when pressed against teeth with normal force.

Magnetic levitation (maglev) designs, used in premium handles, use opposing magnets to suspend the drive shaft and allow motion along multiple axes simultaneously. The result is better amplitude stability under load and the characteristic “buzz” that users associate with professional-grade brushes. Maglev handles cost $1.50–3.00 more per unit at factory gate, which matters when your target retail price is $25–40.

When auditing factories, ask to see the frequency response curve under 150g axial load — the typical brushing force. Stroke amplitude should stay above 3mm peak-to-peak throughout. Factories that cannot produce this data are relying on unloaded bench measurements, which overstate performance by 15–30%.

IPX7 vs. IPX8 for bathroom electronics

IPX7 certifies immersion to 1 metre for 30 minutes. IPX8 certifies continuous immersion beyond 1 metre at depths specified by the manufacturer. For a toothbrush that lives on a bathroom shelf and gets rinsed under running water, IPX7 is the correct and sufficient rating. Specifying IPX8 does not add meaningful protection and adds cost through tighter sealing tolerances.

The sealing challenge in electric toothbrushes comes from two points: the charging port and the power/mode button membrane. USB-C inductive charging eliminates the port entirely — a sealed inductive coil behind the ABS shell has no ingress path. Button membranes use over-moulded silicone gaskets compressed against the PCB; gasket durometer (Shore A 40–60 is typical) and compression percentage affect both seal reliability and button feel.

Test reports for IPX7 should show the unit submerged and operational before and after the immersion period, not just surviving visually. Ask for IEC 60529 test reports from a CNAS- or ILAC-accredited lab. Factory self-certification for IP ratings is common and unreliable.

Handle and brush head customization

For white-label programs, customization scope typically covers: handle colour (RAL or Pantone matching on ABS), logo placement (pad printing or laser engraving on the grip section), charging base design, and packaging.

Brush head sourcing is a separate decision with long-term implications. DuPont Tynex nylon bristles (0.152mm or 0.203mm diameter, end-rounded) are the industry reference for consistent stiffness and wear characteristics. Generic nylon bristles from Chinese suppliers vary more in initial stiffness and degrade faster — a $0.08/head saving that becomes a return rate problem at retail. For brands positioning in the $40+ retail segment, specifying Tynex by name in the BOM is worth the premium.

Replacement brush head compatibility matters if you are building a repeat-purchase model. Many OEM factories sell the same physical head format to multiple brands under different SKUs. Verify whether your handle’s drive shaft coupler is unique or shared — shared couplers mean a competitor’s heads will fit your handle, which complicates brand positioning.

Typical NRE for a custom colour handle: $800–1,500 for colour tooling modification. Full custom mould: $8,000–15,000 for a production-grade injection tool.