I've bought a (slightly fancy) sink for our bathroom, but the tap fittings are confusing me. The sink has three holes; two for the tap handles and one for the spout. There is what looks like a weird flexi that fits to all three underneath, but the diagram has been photocopied so many times it's useless. I can get the flexi into the right position but can't believe it just slots on because I'm sure it wouldn't be watertight. Has anyone seen this sort of thing before? I'd really appreciate any help. It's a similar arrangement to the below...