# 51-400 — Packaging specification equivalence: neck finishes, corrugated grades and pallet standards

For 51-400, specification type is neck_finish; description is 51 mm neck, 400 series (1 thread turn); primary dimension is T max 50.00 mm, T min 49.10 mm; secondary dimension is E max 47.60 mm, E min 46.71 mm; equivalence or compatibility note is 1 Thread turn, recorded from its source on 2026-08-12.

- **Specification ID:** 51-400
- **Specification type:** neck_finish _(our reading, not quoted from the source)_
- **Description:** 51 mm neck, 400 series (1 thread turn)
- **Primary dimension:** T max 50.00 mm, T min 49.10 mm
- **Secondary dimension:** E max 47.60 mm, E min 46.71 mm
- **Equivalence or compatibility note:** 1 Thread turn
- **Additional data:** 400H max 10.75 mm, 400H min 10.00 mm; S max 1.55 mm, S min 0.79 mm; I min 37.60 mm; 6 threads/in.

## What the source says

> 51 | 50.00 | 49.10 | 47.60 | 46.71 | 10.75 | 10.00 | | | | | 1.55 | 0.79 | 37.60 | 6

## Source

- https://www.contapack.com.au/SPI-Neck-Finishes.html

Last verified: 2026-08-12. Review by: 2028-08-11.
Part of [Packaging specification equivalence: neck finishes, corrugated grades and pallet standards](https://referencesource.org/packaging-material-specification-equivalence/).