How many fans per tray : Long stem 3D fans , 12 rows/tray , 20 fans /row , 240 fans/tray Long stem 4D fans , 12 rows/tray , 10 fans /row , 120 fans/tray Long stem 5D fans , 12 rows/tray , 10 fans /row , 120 fans/tray Long stem 6D fans , 12 rows/tray , 10 fans /row , 120 fans/tray Long stem 7D fans , 12 rows/tray , 10 fans /row , 120 fans/tray Long stem 8D fans , 12 rows/tray , 10 fans /row , 120 fans/tray The material of the lashes : The material is black PBT , PolyButylene Terephthalate. It is durable and can stand high temperatures and a variety of solvents (facial cream or cleaners).They are very soft and lightweight and matte dark , just like your own lashes. Specially treated the root : We use a unique double heat bonding method to ensure an ultra light-weight lash without compromising strength and Ultra-thin base, and do not easy to fall apart or separate . The difference between long stem and short stem premade volume fans : Long stem Premade Fans feature a long, thin, base and are easier to apply and usually used for dramatic and dense look. Short stem fans feature a shorter base and wider fan, providing a slightly softer, fluffier look closer resembling a hand made fan .