APC propellers computer-optimized design gives these props a thinner profile and more "bite" with less noise. Lightweight molded nylon construction reduces rotating mass for higher output and longer life. Reinforcing carbon fibers help maintain true, constant pitch at any rpm. "C2" design."
Using on an OS 75 AX 2-stroke in a Four Star 60. I shopped Tower for years without thinking but discovered R/C Planet was a better deal when factoring product and postage costs.