Suited to domestic use this ultrasonic cleaner cleans all your watches, jewellery, fountain pens, dentures, razor heads, printer heads, small silverware and small machined parts. It can also be used to clean circuit boards and components - just remember to let them dry thoroughly before re-applying power! Mains powered and easy to use. Fill the tank with water, add a mild cleaning solution and set the timer. The LCD tells you how long to go and the timer has 5 settings from 90 seconds up to 7 minutes 30 seconds.