A device for occluding hemorrhage in an extremity of a person's limb comprising: (a) an elongate flexible tension-bearing member arranged to be formed into a loop around a person's limb, and (b) a first fastening mechanism arranged to retain the tension-bearing member so as to form and maintain a loop extending around an extremity of a person's limb, (c) wherein the first fastening mechanism is a buckle, which comprises a force- measuring mechanism including a frame, a slide portion movable with respect to the frame, and a spring interposed between the frame and the slide portion, the tension bearing member being arranged to act on the slide portion so that tension in the loop thereby is applied to the slide portion and tension in the loop thereby is applied to the force-measuring mechanism, the force-measuring mechanism thus being able to sense tension in the tension-bearing member in the loop and in response to sensing tension in the tension-bearing member in the loop of at least a first amount to cause the first fastening mechanism to engage the tension-bearing member and thereby establish a predetermined baseline amount of tension in the tension-bearing member in the loop, (d) the device further comprising a tension-increasing mechanism operable, when a baseline amount of tension has been established in the loop by the first fastening mechanism, to increase tension in the loop and reduce the size of the loop around the person's limb to produce a desired amount of tension that is greater than the baseline amount of tension, characterised in that (e) the tension-increasing mechanism is a Spanish windlass, a ratchet, or a winding mechanism, and further characterised in that (f) the device further comprises a quick-release connector attached to an end of the tension-bearing member and wherein the buckle is releasably connected to the quick-release connector. (a) an elongate flexible tension-bearing member arranged to be formed into a loop around a person's limb, and (b) a first fastening mechanism arranged to retain the tension-bearing member so as to form and maintain a loop extending around an extremity of a person's limb, (c) wherein the first fastening mechanism is a buckle, which comprises a force- measuring mechanism including a frame, a slide portion movable with respect to the frame, and a spring interposed between the frame and the slide portion, the tension bearing member being arranged to act on the slide portion so that tension in the loop thereby is applied to the slide portion and tension in the loop thereby is applied to the force-measuring mechanism, the force-measuring mechanism thus being able to sense tension in the tension-bearing member in the loop and in response to sensing tension in the tension-bearing member in the loop of at least a first amount to cause the first fastening mechanism to engage the tension-bearing member and thereby establish a predetermined baseline amount of tension in the tension-bearing member in the loop, measuring mechanism including a frame, a slide portion movable with respect to the frame, and a spring interposed between the frame and the slide portion, the tension bearing member being arranged to act on the slide portion so that tension in the loop thereby is applied to the slide portion and tension in the loop thereby is applied to the force-measuring mechanism, the force-measuring mechanism thus being able to sense tension in the tension-bearing member in the loop and in response to sensing tension in the tension-bearing member in the loop of at least a first amount to cause the first fastening mechanism to engage the tension-bearing member and thereby establish a predetermined baseline amount of tension in the tension-bearing member in the loop, (d) the device further comprising a tension-increasing mechanism operable, when a baseline amount of tension has been established in the loop by the first fastening mechanism, to increase tension in the loop and reduce the size of the loop around the person's limb to produce a desired amount of tension that is greater than the baseline amount of tension, characterised in that (e) the tension-increasing mechanism is a Spanish windlass, a ratchet, or a winding mechanism, and further characterised in that (f) the device further comprises a quick-release connector attached to an end of the tension-bearing member and wherein the buckle is releasably connected to the quick-release connector.