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