gilltech's post in Is this an S30z relay of some sort? was marked as the answer
Goodness knows what that's off, on my early 260 there are several relays that look like the casing but nothing with a fuse externally mounted nor those arms sticking out. The casing looks very weathered, so I presume it comes from the engine bay area.
gilltech's post in Hose Kits was marked as the answer
Just use generic hoses of matching diameter if the 240Z set - which AFAIK is the only type currently available - won't work with your heater.
The pre-moulded shape of one of the 260Z heater hoses on mine was impossible to match without kinking so I just cut it much longer and looped it around in a full circle, it's been like that for decades without an issue and is up under the dash where no-one can even see it anyway.