It is the most kosher a phone can get. A phone called "Quaha-Sarah" (sounds suspiciously like our matriarch), free of the modern day tumah and pritzus of the traditional smartphone, this phone will make you the frummest on the block. If you want to create an even stronger gedder, you can even TAG your kosher phone to ensure your flip phone is truly Mehadrin.
"Yo, is your phone even kosher bro?"
"Yeah, it's a kosher phone!"