Closures and Components Guide
Understanding closures and components
Closures are more than just a functional necessity, they complete the package, ensure compatibility, and shape how consumers interact with your product.
The correct cap, pump, lid, or insert can enhance usability, protect the formulation, and reinforce product positioning, whether it's luxury, practical, or eco-conscious.
This guide outlines the key closures and accessories used across five key product categories, highlighting their purpose, formats, materials, and industry usage.
Diffuser Bottle Components
Common Applications: Home fragrance, reed diffusers, room scent sets
Main Closure Components:
Diffuser Collars
Function: Hold reeds in place and provide a clean finish at the neck.
Types: Crimp-on (for FEA necks), screw-on (for threaded necks).
Materials:
Plastic: Lightweight, cost-effective (matte, gloss, or coloured finishes).
Metal: Adds a premium touch; available in brushed, matte, or polished finishes.
Features:
- Available in flat or domed profiles.
- Used with or without inner stoppers.
- Helps prevent evaporation from the neck area.
Compatibility:
Typically used with FEA15 necks or 28/410 screw necks.
Stopper Inserts / Caps
Function: Seals fragrance inside the bottle during storage, transport, or sale.
Materials:
LDPE (Low-density polyethylene) or silicone for flexibility and tight seal.
Placement:
Press-fitted inside the bottle neck, often under the collar or cap.
Usage:
Helps prevent leaks and loss of scent prior to consumer use.
Diffuser reeds
Function:
Transport and diffuse fragrance oil into the surrounding air.
Types:
Natural Rattan: Traditional, highly absorbent, channels visible.
Fibre Reeds: Uniform appearance, controlled diffusion, colour options (black/white).
Sizes:
Length typically ranges from 150mm–250mm; diameter from 3mm–5mm.
Considerations:
The number of reeds and type should match bottle size and oil viscosity.
Candle Lids
Common Applications: Scented candles, Luxury home fragrance, Wellness sets
Main Closure Components:
Candle Lids
Function:
Protect wax surface, preserve fragrance, add a visual finish.
Materials:
- Wood: Sustainable appeal (e.g., bamboo, ash, beech).
- Metal: Matte black, brushed silver/gold, powder-coated options.
- Glass: Transparent or frosted for upscale ranges.
Types:
- Flat lids, domed lids, recessed lids with or without seals.
- Optional silicone or rubber gasket for tighter closure.
Usage:
Used for shipping protection and in-situ display; enhances perceived value.
Dust Covers
Function:
Lightweight cover to protect wax and wick from dust, debris, or fingerprints.
Materials:
Paperboard or recycled card stock, sometimes with foil or ink printing.
Usage:
Common in retail or gifting formats; cost-effective branding area.
Safety and Warning Discs
Function:
Provide mandatory safety instructions, often included with dust covers.
Materials:
Adhesive-backed vinyl or card.
Compliance:
Required in certain markets for fire safety labelling.
Cosmetic Jar Components
Common Applications: Creams, Balms. Body scrubs, Hair masks, Powders
Main Closure Components:
Screw-Top Lids
Function:
Primary closure for securing contents and ensuring hygiene.
Materials:
- Plastic (PP/PET): Durable, lightweight, available in matte/gloss/colour-matched finishes.
- Aluminium: Offers premium, tactile feel, often anodised for durability.
- Bamboo/Wood Composite: Eco-conscious lines, visual warmth.
Types:
Single-wall (standard), or double-wall (added heft and insulation).
Inner Sealing Inserts
Function:
Provide an additional barrier between product and lid; prevent leakage.
Types:
- Press-fit disc liners: Reusable, placed directly on product surface.
- Wadding inserts: Used in screw caps for soft contact seal.
Materials:
LDPE, foam, or PET.
Tamper-Evident Seals
Function:
Ensures product integrity at point of sale.
Types:
- Induction seals: Applied during filling, require heat sealing.
- Pressure-sensitive seals: Peel-back foil, adhered to the rim.
Usage:
Common in cosmeceuticals or export-ready products.
Beverage Bottle Components
Common Applications: Cold-pressed juices, RTD cocktails, Health tonics, Functional drinks
Main Closure Components:
Twist-Off Caps (Lug Caps)
Function:
Create a vacuum seal, commonly used in hot or cold fill applications.
Materials:
Metal: Coated for corrosion resistance and food-grade safety.
Features:
- May include tamper-evident pop-up button.
- Typically lug-threaded, matches glass bottle finish.
Sizes:
Standard sizes include 38mm, 43mm, 48mm, 58mm, and 63mm.
Crown Caps
Function:
Classic crimp-on closure for carbonated or pressurised beverages.
Materials:
Tinplate steel or aluminium, with inner liner for seal.
Application:
Requires crown capping equipment.
Best For:
Beers, mixers, sodas, bottled cocktails.
Tamper-Evident Shrink Bands / Seals
Function:
Add tamper visibility around the neck/cap junction.
Materials:
PVC or PETG shrink sleeves.
Usage:
Slipped over closure and neck, heat-sealed into place.
Aromatherapy & Dropper Bottle Components
Common Applications: Essential oils, CBD oils, Serums, Tinctures, Facial oils
Main Closure Components:
Dropper Caps
Function:
Dispense product in controlled doses via pipette.
Materials:
- Pipette: Glass or plastic (with various tip shapes).
- Bulb: Rubber (typically nitrile or TPE).
- Collar: Plastic or aluminium.
Types:
Standard, tamper-evident, or child-resistant.
Neck Sizes:
DIN18, GL18, 20/410 are standard.
Orifice Reducers
Function:
Provide flow control by allowing single drops to exit per tilt.
Materials:
LDPE or PP.
Used With:
Screw-on caps (plain or tamper-evident).
Spray Pumps
Function:
Atomise product into a fine mist.
Best For:
Hydrosols, room sprays, facial mists.
Materials:
PP body with plastic or aluminium over caps.
Neck Sizes: 18mm and 20mm most common.
Serum Pumps
Function:
Dispense thicker formulations in precise doses.
Application:
Used for high-viscosity serums and oils.
Comes With:
Clear or opaque overcap to prevent accidental pumping.
Child-Resistant Caps
Function:
Prevent unintended access to products with regulated or active ingredients.
Types:
Push-and-turn or squeeze-and-turn mechanisms.
Compliance:
Often required for pharmaceuticals, CBD or ingestible.
Closure types by category
Diffuser Bottles
Diffuser collars, stopper caps, natural/fibre reeds
Candle Glass
Wooden/metal/glass lids, dust covers, safety labels
Cosmetic Jars
Screw-top lids, sealing inserts, induction seals
Beverage Bottles
Twist-off lug caps, crown caps, shrink bands
Aromatherapy Bottles
Dropper caps, orifice reducers, spray pumps, serum pumps,
child-resistant caps
Key considerations when choosing closures
Neck Finish Compatibility:
Ensure the closure matches the bottle’s neck type (threaded, crimp, DIN, etc.).
Material Suitability:
Consider product formulation (oil-based, water-based, volatile, viscous).
Regulatory Requirements:
Safety, child-resistance, tamper evidence, and labelling standards.
User Experience:
Ease of opening, dosing accuracy.