a thin covering is used for protecting an elongated surgical instrument , and is initially in a telescopically folded configuration prior to insertion of the surgical instrument therein , comprising : an elongated tube having an insertion opening region ; two resiliently deformable leaf - shaped lining members connected to the elongated tube disposed in the insertion region , the lining members each having a central portion and a pair of sides edges . a first of the pair of side edges of one of the lining members is substantially congruent to a first of the pair of side edges of the other of the lining members , and a second of the pair of side edges of the one of the lining members is substantially congruent to a second of the pair of sides edges of the other of the lining members . upon application of forces urging each of the first and the second pair of side edges together , the central portions are spread apart to form a jaw for receiving the surgical instrument .