Sierra 18-5158 Mercury Ignition CoilSierra replacement ignition coil for Mercury Outboards, Mercury Race Outboards, and Mercury Race Stern Drives. High quality brass secondary post for superior corrosion protection; Quality Heatsinks for superb heat dissipation; Meets or Exceeds OEM standards; Interchangeable with: CDI; 184-0004; Mercury Marine; 339-883778A01; 339-883778A02; Mercury Race Outboard; 339-883778A01; Mercury Race Sterndrive; 339-883778A02; 339-8M0077473;