Catalyst Smooth Operator Arm Spacer - 8mm Thick This is the same part that is included with the Smooth Operator 5 Inch frame as standard. Made of 8mm thick 3K matte twill weave carbon fiber.
Catalyst Smooth Operator Electronics Bay Depth Increasing Upgrade The addition of this part will increase the available space in your frame for electronics. It moves the lower bay cover plate down by 2.5mm. Use this part if you need more space for a thick video transmitter, receiver, caps, or buzzers. Fits only the Smooth Operator.
Catalyst Smooth Operator 4mm Rear Arm Brace This arm brace will give extra crash toughness to your frame. Made of 4mm thick 3K matte twill weave carbon fiber. Fits only the Smooth Operator.