Riverge Leader Rings
Each pack contains 10 rings with a card showing suggested knots. Black Nickel comes in either 1.5mm or 2mm size whilst the Stainless Steel are also offered in 3mm size. The 1.5mm size is recommended for the majority of trout applications. 2.0mm is good for lighter salmon and saltwater work (or if the 1.5mm are just too fiddly for you!) and 3.0mm for heavy leaders.
In order to make using the rings easier try threading them onto a piece of wire or a safety pin. Using them direct from the packet at the waterside is challenging!