Abstract: A one piece, sealed ultrasound probe head for measuring volume flow in vessels, which comprises a conventional ultrasound reflector (20) and piezo-electric crystals (23), mounted on a support element (30) which is permanently inserted into a housing (10) which is made of a resilient material and having gel spill guards (11) for limiting acoustic coupling gel spillage; and vessel retainer flaps (12) for retaining the vessel in a stationary position in the probe head. The probe head contains a supporting channel (16) capable of receiving and retaining on its surfaces an acoustic coupling gel. The resilient vessel retainer flaps (12) are capable of being flexed in order to selectively receiving or releasing the vessel into or out of the channel (16), and securing the vessel in a stationary position in said channel in order to allow flow measurement. The probe head in accordance with the invention may be used with any known probe device, including endoscopic probe devices.