C11's have a higher average and peak thrust than regular C's. This allows C11's to launch heavier model rockets. C11's come in a D size casing.
Other Items from Model Rocket Standard and D Engines 1/2A6-2 (3 each) - A8-3 (3 each) - A8-5 (3 each) - B4-2 (3 each) - B4-4 (3 each) - B6-2 (3 each) - B6-4 (3 each) - B6-6 (3 each) - C6-3 (3 each) - C6-5 (3 each) - C6-7 (3 each) -