Hertz ST 35 Bullet TweetersThe ST 35 car audio compression driver, like the ST 25 and the ST 35, employs a CCAR (Copper Clad Aluminium Ribbon) voice coil featuring an extra light aluminium membrane with high thermal dissipation as well as an anodized aluminium body, for maximum damping and vibration rejection. It additionally features a 44 mm (1. 7 in.) voice coil and a powerful ferrite magnet, creating maximum SPL in extreme installations. Data table Size mm (in.) 35 (1. 4)