Perfect for cottage settings, the Harvia 20 Pro ES has a 20-liter water tank on the front of the stove. The large amount of stones translates into a hearty amount of steam and heat for rooms from 283 to 706 cubic feet. Required sauna stones 88 lbs (2 boxes) sold separately. Stylish Black and Stainless Design Requires a minimum of 88lbs of stones (2 boxes-AC3020) Please note that each natural stone is unique in shape and size. We recommend purchasing an additional box of sauna stones to allow you to choose the highest quality of stone for fit, form, and function (Additional freight charges will apply). Installation & Operation Manual Requires a Minimum of 88lbs of stones (AC3020)