You use the integral pump to inflate the the spa very quickly, then attach the pipes as per the dvd instructions, then fill up with water from a hose. The pump then becomes a heater and filter, put the locking lid on and wait for the spar to heat up to the right temperature. There is a inflated bottom very comfortable, the bubbles are really strong. The chemicals are a must for maintaining the health of the equipement, also causes know damage to your health. The plug has rcd attached to it and needs to be tested every time you use it for safety. We just plug it in a few hours before we are going to use it. The size is 81" x 31" takes 900L of water, sits four people very comfortably. On warm summer evenings its so relaxing to sit in and count the stars and a very relaxing sleep follows.