Allstar Performance ALL55055 Arm Bolt for Birdcage Birdcage Bolt - 1/2-20 in Thread - 3.5 in Long - Hex Head - Steel - Cadmium - Sprint Car Birdcage - Each. Birdcage Bolt - 1/2-20 in Thread - 3.5 in Long - Hex Head - Steel - Cadmium - Sprint Car Birdcage - Each.