Tired of squeeshing or scratching the aluminum inserts? The Stainless Steel inserts are stronger and hone to a slightly smoother finish giving additional durability and strength. Each kit includes 8 different bore sizes! Each kit includes the following inserts: .682 .684 .687 .689 .691 .693 .695 .697 Basically youll NEVER be without the right size insert! These are probably the most comprehensive kits in Paintball! You can mix and match different size and color tips and backs as well to literally make hundreds of combinations.