Glass Jar and Bamboo Lid with silicone gasket. Built-in Humidity Sensor. Two-way replaceable humidity packet increases or decreases humidity to ideal 55-65%. S and M jars have a 4 gr packet and L and XL have 8 gr packets. The S, M, and L SmartJars have one humidity packet included, the XL has two. Small - 3.0" H x 2.25" diameter (holds up to 1/4 oz of dried herbs). UV blocking and clear glass