BSPT Version / Size ( British Standard Pipe Thread ) not NPT ( National Pipe Thread - used in USA ) Size.
Part Number 1001605 = One Pair of 1" I.D. Tubes, Large nuts, and Gaskets ( part # 54F ).
Used to connect to Autotrol Valves ( like 163, 168, 263, 268 ) directly or to any Autotrol By Pass. BUT Not in USA. Primarily used in U.K.
SPECIAL ORDER ITEM - 2 week Lead time
Part Number: AP1001605
Usually Ships in 2 to 3 Weeks