Size: 18mm (Neck).
Black Cap complete with Slow Flow Dropper Insert (18/410). Ideal for drop measurements of oils and liquids. 
This listing is for the Cap and dropper insert (closure) only, however you can find all the applicable bottles which it fits listed at the top of the product description, to buy separately. 
 
PRODUCT FEATURES
Cap and insert (slow flow) only; bottle not included
Neck: 18mm
Colour: Black
No minimum order
Sturdy
Lightweight
Facilitates easy drop measurements