Glass Dynamics, LLC offers a full line of caps for your dropper dispensing needs. We offer customization with unlimited options utilizing such styles as Child Resistant, Decorative Over Shells, Standard and Tamper Evident in different sizes, materials and colors. Regardless of your application, Glass Dynamics, LLC can provide you with your dropper bulb solution. Let us meet your needs.

Child Resistant | Decorative Over Shell | Standard | Tamper Evident

Common Glass Packaging Institute (GPI) / Society of the Plastics Industry (SPI) Neck Finishes

Screw thread or continuous thread closure sizes are expressed with two numbers separated by a hypen or slash. The first number refers to the millimeter diameter measured across the inside of the cap's opening or the outside of the bottle's threads. The second number refers to the thread style, "GPI" or "SPI" finish. The Glass Packaging Institute (GPI) and Society of the Plastics Industry (SPI) are responsible for establishing uniform standards for glass and plastic container neck finishes. The neck finish holds the cap, stopper, or closure with protruding threads. A container and its corresponding cap must have matching finishes. For example, a 24/400 bottle will only accept a 24/400 closure. The closure industry does not necessarily adhere to the same standards, so it is often best practice to purchase containers and caps from the same manufacturer when possible.

Neck Finish

• "T" Dimension: The outside diameter of the thread. The tolerance range of the "T" dimensin will determine the mate between bottle and closure.
• "E" Dimension: The outside diameter of the neck. The difference between the "E" and "T" dimensions divided by two determines the thread depth.
• "I" Dimension: The inner diameter of the bottle neck. Specifications require a minimum "I" to allow sufficient clearance for filling tubes. Linerless closures, with a plug or land seal, and dispensing plugs and fitments require a controlled "I" dimension for a proper fit.
• "S" Dimension: Measured from the top of the finish to the top edge of the first thread. The "S" dimension is the key factor that determines the orientation of the closure to the bottle and the amount of thread engagement between the bottle and cap.
• "H" Dimension: The height of the neck finish. Measured from the top of the neck to the point where the diameter "T", extended down, intersects the shoulder.