Simply put, the Silk'n Flash&Go upgradeable cartridge with 120,000 pulses is the last hair removal cartridge you'll ever need. Using Fda-cleared technology, the Silk'n Flash&Go quickly and easily eliminates hair permanently. And with an amazing 120,000 flashes, it's a true lifetime solution for hair removal! Especially useful for treating sensitive areas (bikini line) or smaller, targeted zones (underarms). How it works: Flash&Go uses highly sophisticated Home Pulsed Light (Hpl) technology to safely and effectively provide proven long-term hair removal results. The Home Pulsed Light (Hpl) technology in the device has been designed to capture all the clinical benefits of pulsed light for hair removal at home. A unique skin color sensor is built into the Flash&Go to measure the treated skin complexion at the beginning of each session and occasionally during the session. The skin color sensor ensures that pulses will only be emitted on suitable skin tones. As with professional laser treatments, a series of treatments are required to clear an area of unwanted hair.