Received sample sachets from It's Skin in June 2016. Brand new, no mfg / expiry dates on sachets. Pls buy only if you are comfortable. Volume per sachet also not indicated. S$1 coin is for size comparison only & not included in sale. Pls see Pics 2, 3 & 4 for purpose of each type of serum. I don't use these & apologise that I'll be unable to provide any helpful info here. Can mix : Buy 10pcs for $3.50 mailed Buy 20pcs for $6 mailed Minimum qty for sale is 10pcs. Via mail only. Price includes normal mail within Singapore. I'm not responsible for lost mail.