Part of our series on perfume bottles wholesale — read the overview first if the format is new to you.
Choose a reed diffuser bottle by its neck first: an inner diameter of 18 to 20mm holds five to seven standard 3mm rattan reeds and suits the usual 100ml to 200ml retail diffuser. Specify that bore together with the thread finish, add a plug stopper for transit and a collar for display, and only then settle the shape and decoration. The neck decides how fast the oil evaporates, and the stopper decides whether the bottle arrives full.
Neck bore and reed count
The open area at the neck caps how quickly fragrance can leave the bottle, and the number of reeds determines how much of that cap is used. The body has little say in it.
- Below 16mm: reeds are awkward to insert and customers snap them trying.
- 18 to 20mm: five to seven reeds, the classic retail size.
- 24 to 28mm: eight to twelve reeds for large rooms. More oil evaporates from the wider opening, so the fill volume and the expected life need recalculating.
- Above 30mm: the bottle behaves like an open bowl.
Thread size alone does not describe the opening. A 24-410 finish made with a 19mm bore performs differently from a finish with a 24mm bore, and the gap can amount to a month of product life. Write both figures on the drawing.
Reed length follows bottle height. About one-third of each reed should sit in the oil with two-thirds standing above the collar, so a tall 250ml bottle calls for 25 to 28cm reeds where 20cm is the standard. We specify bottle and reeds as one assembly for that reason.
Planning ranges by format
Use these values to plan a range; each is confirmed on the project drawing before production.
| Format | Capacity | Neck finish / bore | Reed count (3mm rattan) | Bottle weight |
|---|---|---|---|---|
| Round / square diffuser | 50ml / 100ml | 20-410, 18–20mm bore | 5 – 7 | 95g / 160g |
| Round diffuser | 150ml / 200ml | 24-410, 20–24mm bore | 7 – 9 | 210g / 260g |
| Large-room format | 250ml / 350ml | 28-410, 24–28mm bore | 9 – 12 | 330g / 420g |
| Statement / hotel format | 500ml | 28-410, 26–28mm bore | 10 – 12 | 540g |
Plug stopper for transit, collar for use
A diffuser travels sealed and is sold to be used open, so the neck has to work in two states. For shipping, a ribbed plug of PE or TPE is pressed into the bore, usually beneath a screw cap or a decorative collar. It holds against vibration and against the bottle being turned upside down. The customer pulls the plug, and the collar stays as the visible finish.
Leaving the plug out is the usual cause of leaks. Fragrance oil is an aggressive solvent that creeps past a plain screw cap under vibration and temperature swings, and a single leaking bottle soaks the whole carton.
The collar may be aluminium, PP or a wood-look part. It has to thread onto the finish without closing the bore, which is one more reason to state finish and bore separately. 20-410 and 24-410 are the dominant finish standards. Our closure selection hub shows which collar and plug families fit each finish.
Decoration that tolerates fragrance oil
People buy a diffuser as an object for the room before they buy it as air care, so in this category the decoration is effectively the product. Oil will drip on the outside every time reeds are lifted out, and the finish has to be chosen with that in mind.
| Finish | Behaviour with oil | Note |
|---|---|---|
| Internal spray coating | Most durable, because the oil never reaches the coating | The oil deepens the tint seen through the glass |
| External matte or gradient coating | Holds up if an oil-resistant topcoat is specified | State the topcoat in the brief |
| Metallic hot stamping | Survives contact where printed inks can soften | Suited to logos |
| Full electroplating | Used on gift-tier lines | — |
| Frosting | Fingerprints permanently unless specified oil-resistant | Popular in spa channels |
Standard cosmetic frosting and uncoated printed inks show damage within weeks of real use. Dark internal coatings bring a different problem: they hide the oil level, and customers take a bottle they cannot see into as empty or faulty. Leave a clear vertical stripe as a fill gauge, or explain it on the box. Colour has no effect on diffusion itself.
Stock, modified stock or custom mould
| Route | What changes | Best suited to |
|---|---|---|
| Stock mould | An existing flacon with your collar, reeds and coating | First lines, seasonal scents, retail tests |
| Modified stock | A stock body with a custom colour, embossing or a proprietary collar | A core range that needs one ownable detail |
| Full custom mould | A proprietary silhouette and weight, developed over mould-trial rounds | Flagship, design-led collections |
Cost, minimum quantity and timing are quoted per project. They depend on the mould route, the decoration, the quantity and the freight terms. The main saving available to a buyer is consolidating decoration: three colourways run on one coating line cost less to set up than three separate decoration jobs.
The same thinking carries across to neighbouring products. A brand selling candles next to its diffusers can coordinate the glass through our candle jar range so the shelf reads as one family.
Packing and container loading
Decorated diffuser glass scratches easily, so it ships in export cartons with a divider around each bottle. Collars and plug stoppers are either bulk-packed separately or fitted beforehand, depending on how your filling line runs. A 40ft container takes roughly 45,000 to 80,000 units according to format, with the pallet pattern confirmed for each project.
Frequently asked questions
How many reeds does a 200ml diffuser need?
Seven to nine 3mm rattan reeds in a 20 to 24mm bore is the proven setup, giving eight to twelve weeks of scent in an ordinary living room. Adding reeds speeds diffusion and shortens life in proportion, so decide what the pack promises and size the neck to match.
Can a perfume bottle double as a diffuser bottle?
Only when the neck is wide enough. Many perfume flacons have bores under 15mm, which makes reeds hard to insert and diffusion weak. A diffuser bottle needs a bore of 18mm or more, a plug stopper for transit and a collar that leaves the bore open.
What is the minimum order for a custom-coated diffuser bottle?
It is quoted per project, since it depends on the mould and on the line the bottle runs on.