Is it permissible to shave armpit hair with a razor specifically designed for shaving?

It is permissible to remove underarm hair by any means, such as shaving or otherwise. Plucking the underarm is preferable if possible, due to the Prophet's (peace be upon him) saying: "The fitra (natural disposition) is five: circumcision, trimming the mustache, paring the nails, plucking the underarm hair, and shaving the pubic hair."