Great for allowing you to position your water butts further away from each other or the down pipe. You can buy as much as you need in 1m lengths. All pipes that come with fittings, such as the rain trap, have pre-cut pipes which can be replaced by buying the length that you require.If you require: 1m length, purchase 1 unit and you will recieve 1 x 1 meter length 2m length, purchase 2 units and you will recieve 1 x 2 meter length 3m length, purchase 3 units and you will recieve 1 x 3 meter length 4m length, purchase 4 units and you will recieve 1 x 4 meter length and so on... Unfortunately once the pipe has been cut it can't be returned. Fittings are not included with this pipe but can be purchased separately. The inside measurement is 25mm diameter.Recommended accessories for this product Linking kit For Harcostar water buttsOverflow kitPlease Note: This will not fit The 3P Rain water filter.