When should I use 29/25 vs PCO 1881?

29/25 is a light, short still-water finish; PCO 1881 is the global CSD standard that holds carbonation pressure. Use 29/25 for still water and PCO 1881 (or 1810) for carbonated drinks.

Are 29/25 and PCO 1881 interchangeable?

No — they pair with different caps and suit different products. The neck is fixed before blowing and must match your filling line and closure, so confirm it up front.

29/25 vs PCO 1881: Choosing the Right PET Neck Finish

The neck finish is fixed long before the bottle is blown — it must match your filling line and closure. Two of the most common finishes on PET beverage lines are 29/25 (still water) and PCO 1881 (carbonated).

QC inspector placing a neck-finish gauge into a calibrated tray to verify preform dimensional tolerance at Delta El Nile for Industry — Calibrated neck-finish gauges in our QC lab, used to check preform neck dimensions. More about our plant →

29/25 vs PCO 1881 at a glance
Attribute	29/25	PCO 1881
Application	Still water, no pressure	Carbonated soft drinks
Finish design	Light, short water finish	Global CSD standard; thread shorter than 1810
Optimised for	Low cost, high-speed still-water filling	Saving resin while holding carbonation pressure
Matching closure	DEN-CLO-29_25_WATER	DEN-CLO-PCO_1881
Choose when	Still water (or 30/25)	Carbonated soft drinks

29/25 — still water

A light, short water finish optimised for low cost and high-speed still-water filling. Pair it with a lightweight 29/25 closure such as DEN-CLO-29_25_WATER.

PCO 1881 — carbonated

The global CSD standard. Its shorter-than-1810 thread saves resin while holding carbonation pressure, and it pairs with DEN-CLO-PCO_1881. Most of Delta’s CSD preforms — e.g. DEN-CSD-15-PCO1881 — use it.

How to choose

Still water, no pressure → 29/25 (or 30/25).
Carbonated soft drinks → PCO 1881.
Already tooled for a closure? Match the finish to your existing caps and line change-parts.

Filter by neck in the Product Finder, or browse the full SKU reference table.