I used the information in Dr. Falkinham’s Reducing Exposure. I contacted Mary Jo Benak at mj.benak@aqua-tools.com. I had to order a box of 10 but so far the first one is lasting over two months and I expect it to go go three or more. The total cost for all 10 with shipping was $512. The shower head just screwed into our existing handheld hose. I think I was the first individual customer-normally they sell only to hospitals. I was worried about low pressure and low flow but it works great. I still am careful in the shower not to let it get too hot and steamy. Also based on Dr. Falkinham’s info we turned our hot water heater up to 135 degrees. I keep signs posted in all the bathrooms warning visitors that it is hot.