This quartz bonnet is used with Optima 3000, 3000 SCR, and 3x00 RL series instruments. This quartz bonnet is used with Optima 3000, 3000 SCR, and 3x00 RL series instruments. This quartz bonnet is used with Optima 3000, 3000 SCR, and 3x00 RL series instruments.