The NEW OxyGuard Handy Polaris is a portable Dissolved Oxygen (DO) meter for measuring % saturation, mg/L (ppm) and temperature. It has salinity, temperature and barometric pressure compensation The WEDGE-LOCK™ Diffuser is a modular system of diffuser units and end sets that ‘Twist and Lock’ together without the use of tools for significantly reduced set-up time and effort. MBD DIFFUSERS The Microbubble Diffuser (MBD) uses an ultra fine pore ceramic plate which ensures uniform bubbles across its entire surface. Much copied but not equalled, the MBD Diffuser manufactured by Point Four is still the most efficient and reliable diffuser on the market today