Here's how it works: Place in the shower near the plughole. Shower as normal. The lights will flash green, amber and red as Waterpebble memorizes your shower. Then each time you shower, it reduces the amount of time you're allotted fractionally. Waterpebble flashes green to show when to start, amber to signify when you're halfway through, and red when you need to stop. You can purchase it through Dry Planet for £5.31 (about $8 USD) for one unit. What do you think? Good idea or just another unnecessary gadget?