The GPM KG054 front upper arms are CNC machined from 6061 T6 aluminum to provide consistent strength and dimensional accuracy for the Thunder Tiger K-ROCK MT4. The hollowed section reduces rotating mass while preserving section modulus, and Delrin collars are incorporated to tighten tolerances at the ball joint area. These components are manufactured to enhance durability, reduce slop in the suspension linkages, and support more predictable handling under stress.