Instructions:
- Apply to 90 size helicopters, according to the strength character of 90 engine to design, features much increase the horsepower, fuel-saving, low noise, and the highest air exhaust volume on the market.
- Great design and test to three spaces: expansion chamber, accelerated section, silencer chamber, high efficiency and the quick respond of medium speed and high speed, great for 3D flying.
- Use for O.S 91SR/HZ & ALIGN 91H/HP engine.

Specification:
- Size: Ø49.1 x 318 x 81.75mm
- Weight:260g

Accessories:
- Pressure nipple x1
- Exhaust guide x1 (Ø13.5xØ18.5x79.75mm)
- Spacer x2
- Collar screw x2(M4x45mm)
- Spring Washer x2
- Strap x 1(100mm)