Coir block substrate. Burrowing substrate for species from humid enviroments. 100% natural, organic, from sustainable resources. Biodegradable, non toxic, non abrasive. PH5.4 - 6.8 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.