The 9.13145 opens Clockwise (so if Tap is fitted correctly, this will be the Valve for your Right i.e Cold water feed, and the 9.13146 valve opens Anti-Clockwise and will be the valve for your Left i.e. Hot Water feed. See below for more information.

Provided your Tap has been plumbed correctly i.e. that the levers are extended horizontally when Tap in OFF position (and the Hot feed is on the left and the Cold feed on the right), then please note the following: The norm in Industry when referring to Cold or Hot Valves usually means that a Clockwise Opening Valve is known as a Hot Valve (CO) and an Anti-clockwise (ACO) Valve is known as a Cold Valve. However, in a Bridge Lever Tap where the Levers operate Horizontally rather than Vertically, the opposite applies (provided your Tap is plumbed as described above). This means that you would need our 'Hot CO' Valve for the Cold Feed and a 'COLD ACO' for the Hot Water Feed. If in doubt, remove your own valves first and order the same i.e if your own Valve has a blue seal, order the Cold ACO Valve. If your own Valve has a red seal, order the Hot CO Valve. If your own Valves have white seals, then the COLD ACO valve will have NO nick on the nut, whereas the HOT CO valve will have a nick on each side of the 6 sided nut below the splines. If still in doubt, order a Pair. Please see here an example of a Bridge Lever Tap and note that the Hot Valve is on the Cold Side and the Cold Valve is on the Hot Side.