Enough Quantity: Package includes12pcs blackout sleeves, which are sufficient for you to use in daily hydroponic system or replace.[WIDE RANGE OF USES]hydroponics is the most passive form of hydroponics,can be used on a variety of hydroponic plants such as pods,mint,,spider plant,ivy,etc.Help you easily enjoy the of growing plants.There are 12 in the set, enough for daily use and replacement.Easy to Control Light: Our hydroponic jar sleeves allow you control light for different sprout seeds. It can keep light out of your container when hydroponic use, and most green leafy sprouts also prefer indirect sunlight.Product Size: The blackout sleeves fit 32oz wide mouth mason jars quite well, it's not suggest to use on other size of mason jars.Practical and Convenient: Its very easy to use, you can only put the mason jar into the sleeve ,then tighten the adjustable buckle.size: 10 x 16cmMaterial: Polyestercolour: BlackPackage Contents:12 x Blackout SleevesOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.