"This is a great little tyre pressure and tread depth tester.It starts showing PSI when turned on. (the most usful one-also shows Bar and other strange SI units!) It has a useful swivel end to allow easy access to upside down valves.Nice blue backlight on LCD display and also has a bright little LED that can be used to locate the valve cap after using the tester.. The tread gauge is easy to use also with a clear scale of tread depth. It comes with a semi-rigid case also."