A wrist-wearable device uses a loop keeper to securely keep the wristband at place. The loop keeper includes a first protrusion extending from a first inner surface for engaging with one of a plurality of first eyelets of a first wristband and avoiding the first wristband from falling out of the loop keeper to flap around. The loop keeper also includes a second protrusion extending from a second inner surface for engaging with one of a plurality of second eyelets of a second wristband, which the loop keeper is slidably disposed on, so as to provide ease experience for the user from readjust the keeper every time.