This front suspension arm set is a replacement component for HPI Bullet cars and is listed as model BUL-18003-GU. The gunmetal alloy arms are made to fit the front suspension of Bullet 3.0 MT and ST without changing factory geometry.
They serve as a direct-fit spare or a basic upgrade to reduce flex compared with standard plastic arms. Installation is straightforward: remove the hub and pivot pins, swap in the new arms, reinstall the existing hardware and confirm free suspension travel and steering range. No special tools beyond common hobby hex drivers are required.
From a setup perspective, the alloy arms help the front end hold alignment under impacts and aggressive cornering on nitro scale off-road rigs. Expect no major ride height change; handle tuning should focus on shocks and steering geometry adjustments rather than the arm replacement itself.