thingiverse
Adapts a dropper top sold for 1 oz "regular" bottles to fit on bottles with a smaller mouth. See article for details: http://swampcastle.blogspot.com/2011/12/dropper-caps-for-extract-bottles.html
Also available at Shapeways, sadly not cheaply: http://www.shapeways.com/shops/swampcastle?section=Cooking
Instructions
Print cap, purchase dropper set: http://www.kingarthurflour.com/shop/items/dropper-caps-sized-for-1-ounce-bottles#none
Pull dropper out of original cap, and pull/twist into printed cap. Droppers now fit smaller mouth bottles.
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This STL file is compatible with most FDM 3D printers (Creality Ender 3, Prusa MK3S+, Bambu Lab, etc.) and resin printers (Elegoo, Anycubic). Check the original page for recommended print settings and materials.
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