Eheim priming aid for aquarium filters. The priming aid allows you to start the siphon of the filter with the greatest of ease. The connecting pipe is exchanged for the normal suction pipe of the filter thus allowing easy filling of the hose with aquarium water. Available for hose diameters of 12 or 16 mm. Suitable for all makes of external filters which have a tap in the suction area. If not, a tap must be fitted into the suction hose near the filter. The priming aid allows you to start the siphon of the filter with the greatest of ease. The connecting pipe is exchanged for the normal suction pipe of the filter thus allowing easy filling of the hose with aquarium water. Available for hose diameters of 12 or 16 mm. Suitable for all makes of external filters which have a tap in the suction area. If not, a tap must be fitted into the suction hose near the filter