This is a set of K&B Dream Designs 96mm Extreme Edition Tail Blades, and are intended for use with 50 and 600 size helicopters. K&B Dream Designs tail Blades are made from a composition of different materials, with a unique air foil that pulls the air back together to allow the following tail blade to cut through clean, less disturbed air. The airfoil also has a larger surface area which moves more air than longer tail blades. This allows K&B tail blades to be more effective. K&B tail blades offer the performance of carbon fiber but are much more durable and cost far less. When cost performance and durability are considered, K&B tail blades are the best on the market. Tail blades of the same size can be mixed as they weigh the same and colors can be mixed to make your helicopter unique.