What this guide solves: “18/400,” “24/410,” “28/410” — these numbers determine whether your pump fits your bottle, your cap seals your product, and your fill line runs without jams. If you’ve ever ordered 20/410 pumps for 20/400 bottles (they don’t fit), or selected a closure that leaked because the neck finish was “close enough” (it wasn’t), this guide gives you the exact specification language to match any neck finish to any closure.
1. Neck Finish Notation: What Those Numbers Mean
A neck finish designation — e.g., 24/410 — has two parts separated by a slash:
24 / 410
│ │
│ └── THREAD FINISH: 410 = tall / continuous thread profile
│ (see Table 1 below for the 400 vs 410 vs 415 variants)
│
└────── NECK DIAMETER: 24 mm
(measured at the outer thread crest, not the bottle opening)
Table 1: GPI Thread Finish Standards for Cosmetic Bottles
| Thread Finish | Thread Turns | Thread Profile | Common Use | Key Feature |
|---|---|---|---|---|
| 400 | 1.5 turns | Buttress (M-style), medium height | Lotion pumps, fine mist sprayers | Shortest thread height; fast capping |
| 410 | 1.5 turns | Buttress (M-style), tall height | Trigger sprayers, disc top caps, flip tops | Taller thread = stronger grip; more torque tolerance |
| 415 | 2.0 turns | Buttress (M-style), tall height | Child-resistant closures, pharmaceutical | Extra thread turn for tamper evidence |
The critical rule: 400, 410, and 415 are different thread profiles — not interchangeable. A 24/400 cap will not thread onto a 24/410 bottle, and vice versa. The neck diameter may be the same, but the thread depth, pitch, and lead angle differ.
2. Common Neck Sizes: Which Diameter for Which Product
Table 2: Neck Diameter Standards — Diameter × Thread Finish Compatibility
| Neck Diameter | Thread Finish Options | Standard Bottle Opening (ID) | Typical Capacity Range | Common Products |
|---|---|---|---|---|
| 13 mm | 13/415 | 8 mm | 5–15 ml | Eye dropper bottles, lip gloss, sample vials |
| 15 mm | 15/415 | 10 mm | 10–30 ml | Serum droppers, essential oil droppers, roll-on |
| 18 mm | 18/400, 18/410, 18/415 | 12–14 mm | 15–60 ml | Toner bottles, serum bottles, fine mist spray bottles |
| 20 mm | 20/400, 20/410, 20/415 | 14–16 mm | 30–120 ml | Face mist, toner, small lotion bottles |
| 24 mm | 24/400, 24/410, 24/415 | 18–20 mm | 50–250 ml | Body lotion, hand cream, shampoo, body wash |
| 28 mm | 28/400, 28/410, 28/415 | 22–24 mm | 100–500 ml | Trigger sprayers, large lotion bottles, family-size products |
| 33 mm | 33/400, 33/410 | 26–28 mm | 200–1,000 ml | Industrial trigger sprayers, large-format bottles |
| 38 mm | 38/400, 38/410 | 30–32 mm | 500–2,000 ml | Gallon containers, bulk refill bottles |
3. 24/410 Cap: The Industry Workhorse
The 24/410 neck finish is the most common cosmetic bottle standard globally. If you’re launching a body lotion, hand cream, shampoo, conditioner, or body wash, there’s a ~70% chance your bottle has a 24/410 neck.
What Fits 24/410:
| Closure/Pump Type | Compatibility | Notes |
|---|---|---|
| Lotion pump (standard) | ✓ Direct fit | Most lotion pumps are 24/410 by default |
| Foam pump | ✓ Direct fit | Foam pumps share the 24/410 standard |
| Flip top cap | ✓ Direct fit | Most flip tops are 24/410 |
| Disc top cap | ✓ Direct fit | Standard disc top size |
| Screw cap (PP) | ✓ Direct fit | Standard cap size |
| Fine mist sprayer | ✗ Needs 18/400 or 20/410 | Fine mist sprayers use smaller necks |
| Trigger sprayer | ✗ Needs 28/400 or 28/410 | Trigger sprayers use larger necks |
Key specification to verify: A “24/410 lotion pump” from Supplier A and a “24/410 lotion pump” from Supplier B may differ in:
- Dip tube length (must match your bottle height)
- Dip tube inner diameter (must match your product viscosity)
- Closure gasket material (must match your formulation)
- Closure torque specification (must match your fill-line capping machine)
Always request a dimensional drawing with these four dimensions before production.
4. 28/410 Cap: The Trigger Sprayer & Large-Format Standard
The 28/410 neck finish is the trigger sprayer standard and the default for bottles above 200 ml.
What Fits 28/410:
| Closure/Pump Type | Compatibility | Notes |
|---|---|---|
| Trigger sprayer | ✓ Direct fit | 28/400 and 28/410 are the global trigger sprayer standard |
| Lotion pump (large output) | ✓ Direct fit | High-output lotion pumps (2.0–4.0 ml/stroke) |
| Flip top cap | ✓ Direct fit | Large-format flip tops for family-size bottles |
| Screw cap | ✓ Direct fit | Standard large cap |
| Fine mist sprayer | ✗ Not available in 28mm | Maximum fine mist neck size is 20/410 |
| Foam pump | Select models only | Foam pumps are predominantly 24/410; 28/410 foam pumps exist but are less common |
28/400 vs 28/410 — Why Both Exist:
Trigger sprayers traditionally use 28/400 (shorter thread height), while large-format lotion pumps and closures traditionally use 28/410 (taller thread height). In practice, most trigger sprayers today are compatible with both 28/400 and 28/410 bottles because the closure skirt is designed with extra thread depth to accommodate either. However, always verify — some older trigger sprayer molds are 28/400-only.
5. Neck Size Compatibility Matrix: Which Pump on Which Bottle
Table 3: Pump/Closure × Neck Size Compatibility
| Pump/Closure Type | 18/400 | 18/410 | 20/400 | 20/410 | 24/400 | 24/410 | 28/400 | 28/410 |
|---|---|---|---|---|---|---|---|---|
| Fine mist sprayer | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Lotion pump (0.5–1.5 ml) | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Lotion pump (2.0–4.0 ml) | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ |
| Foam pump | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ | ✗ | ✗ |
| Trigger sprayer | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ |
| Oil sprayer | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Flip top cap | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Disc top cap | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Screw cap | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Fine mist sprayer (aluminum sheath) | ✗ | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
6. How to Verify Neck Finish Compatibility Without a Lab
If you’re unsure whether a closure fits a bottle, or comparing samples from two suppliers, use this simple verification sequence:
Step 1 — Visual diameter check: Measure the outer thread crest diameter with calipers. 18 mm = ~18.0 ±0.3 mm. 24 mm = ~24.0 ±0.3 mm. 28 mm = ~28.0 ±0.3 mm. If the measurement is 22.5 mm, it’s a 24 mm neck with slightly under-spec molding.
Step 2 — Thread engagement test: Thread the closure onto the bottle by hand. It should engage smoothly within 1/4 turn and tighten fully within 1.5 turns (for 400/410 finishes). If it takes 3+ turns or cross-threads, the thread finish designation doesn’t match.
Step 3 — Leak test: Fill the bottle 80% with water, thread the closure to 1.5 N·m torque (firm hand-tight), invert, and leave for 24 hours. Any leakage at the neck = inadequate seal. Check the liner/gasket.
Step 4 — Torque removal test: After 24 hours, unscrew the closure. If it requires >2.5 N·m (noticeably more force than standard tightening), the thread finish tolerance may be too tight, risking consumer frustration.
7. Frequently Asked Questions
Q: Can I use a 24/410 cap on a 24/400 bottle?
No. The thread profiles differ in height. A 24/410 cap has taller internal threads designed to engage with a taller (410) bottle thread. On a 24/400 bottle, it will partially engage — maybe 1/2 turn — but will not seal reliably. The closure will feel loose and leak.
Q: What’s the difference between 400 and 410 in practical terms?
The number after the slash (400, 410, 415) is the GPI thread finish designation. 400 has the shortest thread height (~2.5 mm thread depth), 410 is taller (~3.5 mm), and 415 is the tallest (~4.5 mm with an extra turn). Taller threads (410) provide a stronger mechanical lock and more torque tolerance — better for pumps with high return-spring force. Shorter threads (400) are faster to cap and adequate for simple closures.
Q: My bottle is 30 ml — what neck size should I use?
For 30 ml cosmetic bottles, 18/400 or 18/410 is standard. This accommodates fine mist sprayers, dropper caps, and small lotion pumps. 20/410 is also common for 30 ml bottles that use lotion pumps or disc top caps.
Q: Are neck sizes the same across Chinese, European, and US manufacturers?
The GPI (Glass Packaging Institute) and ISO neck finish standards are internationally harmonized. A Chinese 24/410 bottle should fit a European 24/410 closure. However, tolerance variations (±0.2–0.4 mm) across manufacturers mean cross-supplier combinations should always be tested before production. Do not assume compatibility.
Q: What neck size do I need for a trigger sprayer?
28/400 or 28/410. This is the global trigger sprayer standard. If your bottle has a 24/410 neck, it will not fit a trigger sprayer. Plan your bottle neck size based on the pump/closure you intend to use — not the other way around.
8. The Golden Rule of Neck Sizing: Choose the Pump First
Procurement teams often make this mistake: they source the bottle first, then try to find a pump that fits. The result is a limited selection of pumps that happen to match the bottle neck — not the optimal pump for the formulation.
Correct sequence:
- Select the pump/closure based on your formulation (viscosity, chemical compatibility, dosage)
- Identify the pump’s neck finish requirement (e.g., “This lotion pump requires 24/410”)
- Source a bottle with the matching neck finish
This guarantees your pump performs to specification and your fill line doesn’t encounter incompatibility surprises on production day.
Author: Cosmetic Pump Engineering Team Technical Reviewer: Packaging Engineer, ISO 9001 Certified Facility Last Updated: July 2026 Data Source Note: Neck finish specifications based on GPI (Glass Packaging Institute) finishing standards and ISO 12818:2013 (glass packaging — neck finishes). Dimensional tolerances are per GPI recommended practices. Actual manufacturer tolerances may vary by ±0.2–0.4 mm.