These bottles include a black top and dropper insert (orifice reducer). Regular inserts are appropriate for most oils, but if you need orifice reducers for thick oils (like patchouli, sandalwood, vetiver, etc.), let us know in the comments section that you prefer the large reducers. The dropper insert allows you to invert bottle and dispense one drop at a time. Same size cap & dropper insert fits all 4 sized bottles. NOTE: The 15ml (1/2 oz) size bottles are cobalt blue, the rest (5ml, 10ml, 1oz) come in amber).
