In most regards the 38-430 plastic bottle thread is identical to the GL38 glass version, with the noted difference that a small shoulder has been introduced to the mouth of the plastic bottle which raises the required depth of the cap.  This inconvenient change means that the GL38 safety caps offered in the previous pages are too shallow to engage and seal on a plastic 38-430 threaded bottle.  

In our experience, the most common 38-430 plastic bottles are from the Nalgene® brand, although several other manufacturers make bottles with similar finishes which seem to follow the same standard.