Humidity and temperature loggers (Kendal LA9)

Two available... These are to place in an environment whose relative humidity and temperature pattern you want to monitor. For example, a room with damp or that is hard to heat, or if you're dying to know how much extra moisture goes into the air when you hang washing up :) They record data over hours, days, weeks, and then you plug them into a computer USB slot to generate graphs from them. Instructions provided. N.B. Only one of the two has a battery, and it's an unusual battery so you'd probably need to order one for the second logger.