# 7 RW — Hypodermic needle gauge dimensions (OD, ID, wall thickness, dead volume)

For 7 RW, nominal o.d. (mm) is 4.57; nominal i.d. (mm) is 3.81; wall thickness (mm) is .381, verified against its source on 2026-08-27.

- **Gauge number:** 7 RW _(verified: appears in the quote below)_
- **Nominal O.D. (mm):** 4.57 _(verified: appears in the quote below)_
- **Nominal I.D. (mm):** 3.81 _(verified: appears in the quote below)_
- **Wall thickness (mm):** .381 _(verified: appears in the quote below)_

## What the source says

> 7      RW   4.57   4.57/4.60   .381   3.81     3.73/3.89

## Source

- https://nesmalltube.com/wp-content/uploads/2025/06/Metric_Chart_Web.pdf

Last verified: 2026-08-27. Review by: 2029-08-26.
Part of [Hypodermic needle gauge dimensions (OD, ID, wall thickness, dead volume)](https://referencesource.org/syringe-needle-gauge-dimensions/).