Camco 08421 Natural Gas Water Heater Control With 4" Water Column4" water column, 1 1 4" shank length. 1 2" NPT gas inlet by 1 2" inverted flare outlet. Adjustable 70 degree to 160 degree fahrenheit. 79,000 BTU rating. 4" water column 1 1 4" Shank length 1 2" NPT gas inlet by 1 2" inverted flare outlet Adjustable 70 degree to 160 degree fahrenheit 79,000 BTU rating. WARNING: This product can expose you to chemicals including lead which is known to the State of California to cause cancer and birth defects or other