HabiStat Coir Block is a compressed block of burrowing substrate for species from humid environments. It is 100% natural, organic and comes from sustainable resources. Biodegradable, non toxic, non abrasive. Wets quickly and holds water without draining. Instructions. Place block into tray or bucket, add 3 litres of warm water. Top up with more water as required. Leave for 1 hr to allow it to expand fully.