The invention provides a liquid storage installation which includes a tank (70) containing a liquid and a device (10) for measuring and sampling the liquid. The device (10) includes an elongate hollow body (12) having a closed bottom and a plurality of spaced apart sampling ports (20, 22, 24) at spaced apart positions. The device (10) further includes a sleeve (14) which extends around the sampling port and in which corresponding sampling ports (26, 28, 30) are provided at spaced apart positions. The body (12) and sleeve (14) are displaceable relative to one another between an open position in which the sampling ports are in register permitting liquid flow between the tank and the interior of the body and a closed position in which the ports are out of register and flow between the tank and the interior of the body (12) is prohibited.