For double poly greenhouse you'll need an air inflation kit to provide the "dead air space" between the two covers. Our air inflation kit contains the cover blower (60 cfm), the air jumper tube, damper and the mounting bracket. Outside vent not included with the greenhouse inflation blower.
CA Proposition 65 warning:
This product could expose you to lead and/or other chemicals known to the state of California to cause cancer or reporductive harm. For more information, please visit www.p65warnings.ca.gov.