This new flow indicator provides optical indication of coolant flow. The flow sets the wheel into motion, hence showing the flow. Faults such as kinked tubing or similar can hence be controlled optically. The filter has proven not to be obstructive even at higher flow rates. The filter itself catches even the smallest particles in the loop. This is especially useful if micro-structure waterblocks are used as the filter prevents clogging of the cooling structure. Important: Please note the flow direction. Should the filter be clogged it can be cleaned by flushing it in the opposite direction. Mounting notes: Overtightening may result in cracks in the Plexi. The tightening force may be no more than 6Nm Please note: Due to the sensitivity of the Plastic the use of coolants with chemical additives or colourings may result in cracks. These cracks may result in leaks or breaks.