A device (1) comprises a sheath (9) for protecting a balloon catheter (2) from contamination with bodily fluids and other matter during the carrying out of a procedure or investigation at a remote site in a human or animal body. The sheath (9) defines a catheter accommodating portion (14) and a balloon accommodating portion (15) for accommodating a catheter (4) and a balloon (8) of the balloon catheter (2) therein. The sheath (9) is of a flexible material having a closed distal end (11) and a proximal opening (13) at a proximal end (10) thereof to a hollow interior region (12) within which the balloon catheter (2) is accommodated. A guide wire engaging distal portion (19) engages and locates a guide wire (7) within the sheath (9). The balloon accommodating portion (15) permits inflating of the balloon (8) to a predefined volume.