Canuck4 and Twitched are correct and if you cant find 18G pins in your area what I did was go to your local Pharmacy and get a baby oral medicine droper which is 10cc all platic barrel with cap and just count out the drops from 6-7cc mark as this point will be most accurate and that will give you the amount of drops = 1cc/4mg then divide total drops from the 1cc by 4 thus giving you drops per 1mg.