A flexible band which is capable of being adjusted around a limb. The main use in medicine is at low pressure (about 60mmHg) to allow for dilatation of veins to enable access for venepuncture. In this context it is usually a flat band of elastic material with either a Velcro™ fastening at the ends or a clip of metal or plastic with a quick release fitting.
A more heavy duty and reliable tourniquet is required to achieve haemostasis:
- Trauma as a temporary measure (see below).
- Surgery, especially in orthopaedic and plastic surgery to reduce blood loss and permit a clear operative field.
- Bier's block to confine local anaesthetic to the limb.
In major trauma or battlefield conditions, there is a much sturdier device capable of much higher pressure (above systolic blood pressure) used to stop major haemorrhage in the case of traumatic amputation or major injury to a large artery or vein. Any tight material may do but the CAT (Combat Action Tourniquet) produced for the American forces  is an example of a device specifically designed for such situations.