Cast iron effect plastic gutter. The 112mm Original Half Round Gutter from The Cast Iron Effect Company, is the most widely used choice of gutter profiles - offering a practical and easy to install plastic cast iron effect guttering solution. Users benefit from a good flow capacity, a pre-fitted gutter seal retaining clip system for a fast user friendly installation and pre-lubricated seals. Users will find this range of products very easy to fit, economical and will provide the best finish.