In certain applications you will need silica conditioned to a certain relative humidity to help acclimate an object such as wood or ivory and keep it from splitting or cracking. Each Rhapid Pak unit contains .5 lb (250 grams) of pre-conditioned to 40% RH Rhapid Gel in a moisture permeable bag (dimensions L x W x H: 6.5" x 5" x 0.6" [16.5 x 12.5 x 1.5 cm])(6 Paks per order).Based upon standard museum recommendations, one Rhapid Pak will condition 2 to 4 cubic feet of case volume.