SankalpIndian PET water bottles run on a small set of published neck finishes. Still water sits on the lightweight three-start finishes defined by CETIE, principally 29/25 and 30/25. Carbonated and sparkling lines sit on 28 mm PCO 1810 or the lighter PCO 1881 from ISBT, with 26/22 GME 30.40 the newer option. Aluminium ROPP closures use their own convention: a diameter and a height in millimetres, such as 28/15, because the thread is formed onto the neck during capping rather than moulded in advance.
This page is the market survey. For the notation itself, what 38-400 cap size means is the code reader.
Key takeaways
- PET neck finishes are published voluntary standards, mostly from CETIE (the GME data sheets) and ISBT (the PCO Threadspecs).
- Still water uses three-start finishes: 29/25 under GME 30.26, 30/25H under GME 30.21, and 38/33 under GME 30.25 for aseptic still lines.
- Carbonated lines use 28 mm PCO 1810, the lighter PCO 1881 finalised by ISBT in 2009, or 26/22 under GME 30.40.
- 26/22 GME 30.40 is a single-start finish, 15.1 mm high on a 2.3 mm pitch, for carbonated beverages and tethered closures.
- Pack size does not determine the finish. The bottler and the preform supplier do.
- R Vision manufactures 28/15 mm aluminium ROPP closures only. Every other format here is industry reference, not an R Vision product.
The formats, and the standards that define them
| Format | Defining standard | What the standard specifies it for |
|---|---|---|
| 26/22 | GME 30.40, CETIE | Carbonated beverages. Single-start thread, 15.1 mm high, 2.3 mm pitch, with space above and below the ring for a tamper band and a tethered cap |
| 29/25 | GME 30.26, CETIE | Flat waters and non-carbonated beverages. Three thread starts, 12.6 mm, aseptic filling and nitrogen injection |
| 30/25H | GME 30.21, CETIE | Flat waters and non-carbonated beverages. Three thread starts, 18.5 mm, aseptic and nitrogen-injection filling |
| 38/33 | GME 30.25, CETIE | Still waters and non-carbonated beverages. Three thread starts, 16.5 mm, aseptic filling with nitrogen |
| PCO 1810, 28 mm | ISBT Threadspecs | The long-standing 28 mm carbonated soft drink finish |
| PCO 1881, 28 mm | ISBT Threadspecs | The lightweight 28 mm CSD finish, agreed in 2007 and finalised in 2009 to cut preform and closure weight |
| 28/15 ROPP | Diameter and height convention, not a GPI or PCO code | Aluminium roll-on pilfer-proof closures. 28 mm diameter, 15 mm cap height |
CETIE is the international technical centre for bottling that publishes the GME finish data sheets as free voluntary standards. ISBT is the International Society of Beverage Technologists, whose Threadspecs are voluntary, beverage-focused finish guidelines published free of patent or royalty restrictions. Neither body is Indian, but both sets are what Indian preform and closure tooling is cut to, which is why a finish code travels across suppliers.
What drives the format
Lightweighting. The dominant force. PCO 1881 exists because the industry agreed to shave material out of the 28 mm CSD neck and the closure that fits it, and GME 30.40 goes further by dropping the thread diameter to 26 mm. Less resin per neck compounds across millions of units.
Fill method. Carbonated products need a finish rated to hold internal pressure, which is why the CETIE sheet for GME 30.40 states a carbonation rating and the still-water sheets do not. Aseptic and nitrogen-dosed still-water lines pull toward the wider three-start finishes. Hot fill adds its own constraint, because the neck has to keep its geometry at fill temperature.
Tethered closures. GME 30.40 was defined with space above and below the pilfer ring so a tamper-evident band and a cap tether can both live there. Where tethering is required, the finish is chosen for it.
Bottles against jars. The 20 litre returnable jar is a different product. Those closures are wide press-on or screw fittings sized to the jar moulder’s own tooling rather than to a published standard, so there is no code to quote. Confirm the fitting with the jar supplier.
Pack size is a weak signal
The common question is “what neck does a 1 litre water bottle use in India”. It depends on the bottler. Two 500 ml still water bottles from different plants can sit on different finishes, because the choice follows the plant’s preform tooling, its filler, its capper and how far it has gone down the lightweighting path. Read the finish off the preform technical drawing, or ask the preform supplier for the GME or PCO reference in writing. Working from a physical sample instead, how to measure bottle cap size covers the diameter step and the ROPP cap size chart the diameter and height pairs.
Where an aluminium ROPP closure fits
A plastic screw cap and an aluminium ROPP closure are not two versions of the same thing, and they are not ordered the same way.
| Plastic screw cap | Aluminium ROPP cap | |
|---|---|---|
| Neck reference | GME or PCO finish code, thread already moulded into the neck | Diameter and height, thread rolled onto the neck at capping |
| Tamper evidence | Moulded band that breaks or a tethered band | Integral pilfer band formed during application |
| Typical use on water | Standard retail still and sparkling PET | Premium and brand-led water, glass, and lines wanting a metal seal |
| Line equipment | Capping head torques a pre-threaded cap | Roll-on head with thread and skirt rollers |
| Ordering unit | Finish code | Diameter and height, plus finish and decoration |
The trade-offs on a water line are worked through in ROPP cap vs screw cap and types of water bottle caps. R Vision’s Aqua Cap is a 28/15 mm aluminium ROPP closure with a TPE liner, rated to 8 bar, and 28/15 mm is the only size R Vision makes. Treat the PET finishes above as reference for specifying your bottle, not as caps to order from us.
Frequently asked questions
What neck size do Indian packaged water bottles use?
Still water PET bottles in India commonly sit on the three-start lightweight finishes defined by CETIE, principally 29/25 and 30/25, while carbonated and sparkling lines use 28 mm PCO 1810 or the lighter PCO 1881, with 26/22 under GME 30.40 the newer option. The finish is chosen by the bottler and its preform supplier, not fixed by pack size.
What is 26/22 GME 30.40?
It is a PET neck finish defined by CETIE for carbonated beverages. The finish is 15.1 mm high with a single-start thread on a 2.3 mm pitch and a thread diameter of about 26 mm, which is why it is written 26/22. It was designed to cut weight out of the neck and the closure, and it leaves room above and below the pilfer ring for a tamper-evident band and a tethered cap.
What is the difference between PCO 1810 and PCO 1881?
Both are 28 mm carbonated soft drink neck finishes published by ISBT. PCO 1810 is the older, taller finish. PCO 1881 is the lightweight replacement agreed at ISBT in 2007 and finalised in 2009, removing material from the preform neck and the closure while keeping the thread engagement needed to hold carbonation. They are not interchangeable.
Is 28/15 the same kind of code as 29/25 or PCO 1881?
No. In 28/15 the numbers are a neck diameter of 28 mm and a cap height of 15 mm, both real measurements, because an aluminium ROPP cap has no thread until the capping head rolls one onto the neck. In a PET finish reference such as 29/25 or PCO 1881 the numbers point to a published thread specification with a defined profile, pitch and height.
What closure do 20 litre water jars use?
Returnable 20 litre jars use wide press-on or screw fittings sized to the jar moulder’s own tooling rather than to a published neck-finish standard, so there is no GME or PCO code to quote. Confirm the fitting with the jar supplier before buying closures. Aluminium ROPP closures are not used on this format.
Sources
- CETIE finish data sheets (GME), for GME 30.21, GME 30.25, GME 30.26 and GME 30.40
- ISBT Threadspecs, International Society of Beverage Technologists, for PCO 1810 and PCO 1881
Voluntary standards are revised, so confirm the current data sheet before cutting tooling. More sizing references sit on Learn, or contact R Vision.