The filter/diffuser on the end of my kitchen tap appears to have a 25-26mm (1"?) thread (male on diffuser, female on tap). I just bought in error a neat metal swirl that has a 22mm female fitting and a 22mm to 24mm male to male plastic adaptor. Can't find anything similar that fits my tap, which is fairly new, nor an adaptor to fit the 26mm female tap outlet. Any ideas? And what sort of range of different tap outlet threads exist?