A medical device for tissue ligation comprises a band having perforations and rungs defined therein. A locking case is connected to the band and has a channel dimensioned for reception of the band. A locking member of the locking case is configured to interlock perforations and rungs defined in the band. The channel comprises an arching portion into which the band at least partly protrudes by arching over the locking member when the locking member engages a rung of the band.