# Nonin Onyx Vantage 9590 vs Contec CMS50D: specs and price compared

A sourced, side-by-side comparison of the Nonin Onyx Vantage 9590 (Nonin Medical) and Contec CMS50D (Contec Medical Systems) among pulse oximeters. Contec CMS50D is the cheaper of the two at $8.99.

## Side by side

| Spec | Nonin Onyx Vantage 9590 | Contec CMS50D |
| --- | --- | --- |
| US price | $199 | $8.99 |
| Brand | Nonin Medical | Contec Medical Systems |
| 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 |

## Key differences

- 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

## Sources

- Nonin Onyx Vantage 9590: https://www.nonin.com/wp-content/uploads/2018/09/Instructions-for-Use-9590.pdf (nonin.com, verified 2026-08-01)
- Contec CMS50D: https://www.contecmedsystems.com/showroom/contec-cms50d-fingertip-pulse-oximeter-spo2-sensor-ce-and-fda-approved.html (contecmedsystems.com, verified 2026-08-01)

Canonical: https://frontdeskreview.com/gear/pulse-oximeters/nonin-onyx-vantage-9590-vs-contec-cms50d/
Cite: Per The Front Desk Review, Nonin Onyx Vantage 9590 ($199) vs Contec CMS50D ($8.99) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/pulse-oximeters/nonin-onyx-vantage-9590-vs-contec-cms50d/
License: CC BY 4.0.