A loading unit includes a shell assembly and a locking band. The shell assembly has a proximally extending annular body. The annular body defines two hook openings that oppose one another, a lug opening positioned between the hook openings, and a central passage for receiving a portion of a surgical instrument. The locking band has an arced body with two ends, a retention hook positioned adjacent each end of the body and extending from the inner surface of the body. Each of the retention hooks is disposed within a respective one of the hook opening to retain a respective one of the ends of the locking band to the annular body. The lug is disposable through the lug opening into the central passage to secure the loading unit to a surgical instrument.