Nonin Medical
Nonin Onyx Vantage 9590
$199
Best Pulse Oximeters · head-to-head
Nonin Onyx Vantage 9590 vs Contec CMS50D
A sourced, side-by-side comparison. Contec CMS50D is cheaper at $8.99. Every spec and price links to its source.
Contec Medical Systems
Contec CMS50D
$8.99Cheaper
Which is better: the Nonin Onyx Vantage 9590 or Contec CMS50D?
On the specs we track, they're closely matched. The Contec CMS50D is the cheaper at $8.99.
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | Nonin Onyx Vantage 9590 | Contec CMS50D |
|---|---|---|
| US price | $199 | $8.99 |
| Brand | Nonin Medical | Contec Medical Systems |
| Released | — | — |
| Spo2 range | 0-100% | 0-100% |
| Spo2 accuracy percent | 70-100% Arms ±2 digits (finger/thumb, no motion); toe accuracy ±2 (70-90%) / ±3 (90-100%) | ±2% (70-100%); ±4% under weak/low-perfusion signal conditions |
| Pulse rate range bpm | 18-321 bpm display; declared accuracy 20-250 bpm ±3 digits (40-240 bpm ±3 digits low perfusion) | 30-250 bpm |
| Display type | Numeric LED display with tricolor pulse-quality indicator | LED display |
| Perfusion index | No | No |
| Continuous monitoring | No | No |
| Bluetooth | No | No |
| Battery life hr | 36 | 24 |
Sources — Nonin Onyx Vantage 9590: nonin.com (verified 2026-08-01). Contec CMS50D: contecmedsystems.com (verified 2026-08-01).
What's the difference between the Nonin Onyx Vantage 9590 and Contec CMS50D?
Where the two actually differ on the specs we track (4 of 8). Matching specs are omitted.
- Spo2 accuracy percent: Nonin Onyx Vantage 9590 70-100% Arms ±2 digits (finger/thumb, no motion); toe accuracy ±2 (70-90%) / ±3 (90-100%) vs Contec CMS50D ±2% (70-100%); ±4% under weak/low-perfusion signal conditions
- Pulse rate range bpm: Nonin Onyx Vantage 9590 18-321 bpm display; declared accuracy 20-250 bpm ±3 digits (40-240 bpm ±3 digits low perfusion) vs Contec CMS50D 30-250 bpm
- Display type: Nonin Onyx Vantage 9590 Numeric LED display with tricolor pulse-quality indicator vs Contec CMS50D LED display
- Battery life hr: Nonin Onyx Vantage 9590 36 vs Contec CMS50D 24