My Comments on these props.

Balance is good but not perfect. Nice thing i noticed about these are the high efficacy at hover (9 amps Mini T Copter). these are great for flying around on 3 cell packs.

Inner diameter: (Prop Mount) 5mm

6040 High Efficiency, Good Balanced Props

4 Props total (2CW, 2CCW)

 PC + glass fiber material is made of a high quality, flexible and durable plastic that can easily survive crashes and tree clips.

They are NOT Indestructible, but they are durable.