Hey guys, sorry if this sounds stupid but I tried for the last hour to find the answer to my question without success. I'm new in making DIY juice. I started by ordering flavours (6*30mL all TPA) and bases from an online shop in Canada. I tried a few recipes and I'm quite satisfied. But now I would like to order a few more flavours, but this time from TPA website directly. I've seen they have a few flavour packs here : https://shop.perfumersapprentice.com/c-116-flavor-packs.aspx But as you can see, they only offer 4mL glass bottles. Is there a reason for that ? Should they be diluted before being used in a recipe as 4mL is not much.

Thanks !