TE Plus Assembled Droppers: Sizes, Fit and Filling-Line Tips

Buying a dropper closure as three loose parts (teat, collar, pipette) gives you flexibility, but it also gives you more to inspect, store and assemble. If your product does not need a custom combination, a ready-assembled dropper with a tamper-evident collar saves steps. This article looks at our TE Plus range: what is in it, how the sizes line up with bottles, and what to check before you run a batch.

What is in a TE Plus dropper

Every TE Plus dropper in the Tamper Evident Droppers “TE Plus” category is delivered fully assembled and is built for a DIN18 (GL18) bottle neck. The specification is the same across the range, apart from pipette length:

Teat: black NBR rubber.
Collar: black polypropylene (PP) with a breakable security ring, so a first opening is visible to the end customer.
Cap style: a prominent cap, which gives the closure a more pronounced look on the shelf.
Pipette: glass with a straight tip, with the length matched to the bottle volume.

The product pages list the available collar options for each size, so check the page for the exact variant you want before ordering.

Glass dropper pipette with straight tip next to a bottle

Matching dropper size to bottle volume

The range covers seven bottle volumes. The pipette length grows with the bottle, so the tip reaches the bottom without pressing against the glass.

Bottle volume	Pipette length (straight tip)
5 ml	48 mm
10 ml	58 mm
15 ml	63 mm
20 ml	70 mm
30 ml	77 mm
50 ml	90 mm
100 ml	108 mm

For example, the 30 ml TE Plus assembled dropper with a 77 mm pipette is the match for a standard 30 ml DIN18 bottle.

Why the table is only a starting point

Bottles with the same nominal volume are not always the same height. A tall, narrow 30 ml bottle and a short, wide one can need different pipette lengths. The nominal volume tells you which listing to start with. Your own bottle tells you whether it fits. Before you commit to a full order, put a sample dropper into a sample bottle and check three things:

The pipette tip sits just above the base of the bottle, not jammed into it.
The collar seats fully on the neck without a gap.
The security ring sits evenly around the neck, with no tilt.

If you are still choosing a bottle, our DIN18/GL18 dropper bottles are made for this neck finish. Using both from the same range removes the most common source of mismatch.

What the tamper-evident ring does and does not do

The breakable ring is a visual indicator. When the cap is first turned to open, the ring separates from the collar. A customer can see that the bottle was opened before. This is useful for products where trust matters: CBD oils, supplements, essential oils, and serums sold online or through third-party retailers.

It is worth being precise about what it is not. It is not a child-resistant mechanism, and it is not a hermetic seal. If you need child resistance, look at the CRC/TE droppers instead. Whether you need tamper evidence, child resistance or both depends on your product and the markets where you sell it. We recommend confirming this with your regulatory contact, since we cannot decide it for you.

Filling line with small glass bottles being capped

Filling-line tips

Fill first, then fit the dropper

Fill the bottle to the level you have validated, leaving headspace for the pipette. When the pipette goes in, it displaces liquid. In a nearly full bottle, the displaced liquid can rise into the neck and spill over the thread. Test the fill volume with the actual dropper fitted, not with an empty bottle in mind.

Seat the dropper straight

Because the teat, collar and pipette are already joined, you apply the unit in one motion. Lower the pipette into the bottle vertically, then start the thread by hand or on the machine. A pipette that enters at an angle can touch the neck edge and cross-thread the collar. Whether you cap by hand or with a machine, the goal is the same: a straight start and a firm, even close.

Do not over-tighten

With a tamper-evident collar, there is one more reason not to over-tighten. Excessive force during capping can stress the ring or the thread. We do not publish a torque figure for these droppers, so set your own torque on a trial run using your bottles and your product, then check the result. If you use a machine, our packaging machinery category is a good place to start looking at capping options.

Inspect the ring after capping

Make a quick visual check part of the line routine. Look for a ring that is intact, level and not visibly stretched. Remove any unit where the ring is cracked or has lifted. Do this on a sample basis for large batches, and note the results in your batch record.

Product compatibility: test with your formula

The teat is NBR rubber and the collar is polypropylene. Different formulas affect rubber in different ways. Strong essential oils, solvents and some carrier oils can cause teats to swell, soften or change over time. We do not provide compatibility results for your formula, so run a stability test with the finished dropper on your product, in your bottle, under the storage conditions you expect. If the NBR teat is not a good match, a different teat material can be assembled on request. Our article on choosing dropper bulb materials covers the trade-offs in more detail.

Common mistakes to avoid

Ordering by volume only. Check the bottle height and the pipette length, as described above.
Skipping a sample run. A short trial on your line costs little and shows thread, ring and fill-level issues before they affect a full batch.
Mixing neck finishes. These droppers are DIN18 (GL18). A bottle with another neck type will not seal properly.
Assuming tamper-evident means child-resistant. They are different features with different purposes.
Storing assembled droppers carelessly. Keep cartons closed, dry and away from heat and solvents until use. Crushed or stressed teats and collars cause problems later.

When a ready-assembled dropper is the right choice

A TE Plus dropper suits you if you need a clean, black closure with visible tamper evidence, a standard DIN18 neck, and a quick path from order to production. Lead time is typically 3-5 working days from payment, and we ship across the EU and the UK. If you need a different colour, teat or pipette style, we can assemble custom combinations, and the parts are also sold separately in Collars “SecureSeal” and related categories.

FAQ

Which bottle neck do TE Plus droppers fit?

All sizes are made for DIN18 (GL18) necks. Always test a sample on your own bottle to confirm the fit.

How do I choose the pipette length?

Start with the listing that matches your bottle volume, then check the bottle height. The tip should sit just above the base without touching it hard.