A system for removing a tissue specimen through a body opening defining a tissue margin, the system comprising: a shield including a band made of flexible cut-resistant material; the band having an inner surface and an outer surface interconnected by a top end and a bottom end and by a first end and a second end; the band being configured to define a central lumen having a longitudinal axis; the central lumen having a lumen diameter that is perpendicular to the longitudinal axis; wherein the band is split such that the band is movable into a reduced configuration wherein at least a portion of the outer surface at the first end overlaps and is in juxtaposition with the inner surface at the second end to form a spiral and define an overlapping portion; wherein the shield is configured to have a variable lumen diameter by varying the overlapping portion; and a locking mechanism configured to fix the lumen diameter; the locking mechanism includes at least one inner abutment (5020, 5022, 5026) formed on the inner surface; wherein the at least one inner abutment (5020, 5022, 5026) extends along the longitudinal axis along at least a portion of the band between the top end and the bottom end; wherein the first end is configured to contact the at least one inner abutment (5020, 5022, 5026) to prevent reduction of the lumen diameter in a locked configuration; the first end being demarcated by a marker indicating which of the first end or the second end of the band resides inwardly toward the longitudinal axis wherein the marker is configured to facilitate withdrawal or release of the shield from the locked configuration and to serve as a directional purpose indicating which side of the shield is up. a shield including a band made of flexible cut-resistant material; the band having an inner surface and an outer surface interconnected by a top end and a bottom end and by a first end and a second end; the band being configured to define a central lumen having a longitudinal axis; the central lumen having a lumen diameter that is perpendicular to the longitudinal axis; wherein the band is split such that the band is movable into a reduced configuration wherein at least a portion of the outer surface at the first end overlaps and is in juxtaposition with the inner surface at the second end to form a spiral and define an overlapping portion; wherein the shield is configured to have a variable lumen diameter by varying the overlapping portion; and a locking mechanism configured to fix the lumen diameter; the locking mechanism includes at least one inner abutment (5020, 5022, 5026) formed on the inner surface; wherein the at least one inner abutment (5020, 5022, 5026) extends along the longitudinal axis along at least a portion of the band between the top end and the bottom end; wherein the first end is configured to contact the at least one inner abutment (5020, 5022, 5026) to prevent reduction of the lumen diameter in a locked configuration; the first end being demarcated by a marker indicating which of the first end or the second end of the band resides inwardly toward the longitudinal axis wherein the marker is configured to facilitate withdrawal or release of the shield from the locked configuration and to serve as a directional purpose indicating which side of the shield is up.