The lastolite ezybalance underwater greywhite card is a 30cm 12 card that helps to determine the exposure adjust the lighting ratio and check the light distribution it is a very handy double sided pop up grey white card that simplifies exposure and colour corrections when working under different lighting conditions the lastolite ezybalance underwater card is made from a waterproof material which means it can be used on location without the worry of damage by moisture and even underwat