As a general rule, #5 (gold) is for 2-4X scopes, #1 (yellow) is for 2-6X, #1.5 (Ice Blue) is for 3-8X scopes, #2 (Green) is for 4-8X and #3 (Red) is for 6-8X scopes. Weigh 3.5 grains. October Mountain Products 60968 Vibe Purple Green Bow String Silencer 2Pk.