This clear plastic rain gauge's funnel directs its collected rain into a calibrated inner measuring tube with a capacity of 25mm rainfall. This is easily read without opening the rain gauge. When rainfall exceeds 25mm, the excess rainfall overflows into the outer collecting cylinder, which has an overall capacity of 275mm. Measuring rainfall above 25mm is then done by filling the inner removable measuring tube with the collected rainwater in batches of 25mm until the outer cylinder is empty. Constructed of high quality plastic designed for permanent outdoor use.