Silica gel sachets or bags, are simply flexible 'containers ' of silica gel. The sachet material has to be robust and capable of withstanding normal handling whilst importantly being able to breathe. This means that water molecules can pass through the material and be adsorbed by the silica gel. Standard sachet materials are tea-bag paper, fabric, cotton Some sachets have heat-sealed seams, others are sewn. We produce a range of standard size silica gel sachets using non-indicating (white) or indicating (orange/green, orange/colorless or blue) silica gels. In the latter case, the colours of the gels are visible through the sachet paper or fabric. Self-indicating silica gel sachets are often useful in test situations, to confirm the suitability of the sachet size chosen, or in cases where an item is frequently inspected and the sachet can be replaced if it has become exhausted.