Rion Greenhouse Rain Gutters The RionTM Greenhouse Rain Gutter is designed to mount on the sides of your greenhouse to help direct rain water around your greenhouse. The included down spout can also be directed into a barrel to collect for watering plants. (barrel not included) This rain gutter will accommodate one (1) 8' side of your greenhouse. For installation on both sides you will need to purchase two (2) of this item. To accommodate Lengths greater than 8' you will need to purchase a 4' gutter extension Kit for every 4' you wish to extend your gutter system. The RionTM Greenhouse Rain Gutter 4' extension is designed to extend your greenhouse gutter in 4' Lengths. You will need to purchase one (1 ) extension kit for every 4' Length you wish to add rain gutter to. For example if you have a Rion Professional GH48 16' long greenhouse, you would need 1 gutter kit, plus 2 gutter extensions. This item does not include collection barrel.