Bio-Rad offers two dispensers for antimicrobial susceptibility disk testing. The 7-disk dispenser is designed for 90 mm or 100 mm round plates and features a unique central position. The 12/16 disk dispenser can be used for 150 mm round plates (12 disks) or 120 mm square plates (16 disks). No height adjustment is required for different volumes of media (3 to 5 mm depth) in plates. The cartridges click into their correct locations, and a plastic skirt ensures that each agar plate is precisely centered every time the dispensers are used. The unused position can be blocked to avoid plate-to-plate contamination. Disks are dispensed and tamped onto the agar. The dispenser storage box includes desiccant to protect antibiotic disks from moisture when the dispenser is kept at +2–8°C.