Hello,

Is the thread on a 15mm compression fitting 1/2 inch BSP? And on a
22mm fitting 3/4 inch?

I ask because Screwfix sell male compression couples that have a 15mm
nut on one side and a 1/2 inch male thread on the other. I wondered
whether this is just a straight 15mm couple with one nut removed or
are they different?

Similarly is a 22mm to 3/4 inch couple just a 2mm straight couple with
one nut removed?

Thanks.
Stephen.