2" BSP parallel (G2 / BSPP): 59.614 mm major diameter, 11 thread, parallel, 55 degree. What it fits and the adapters to join it to other hose and tap threads.
Updated 05 September 2026.
2" BSP parallel (G2 / BSPP) (G2)
Where G2 is used, its real dimensions, and how to connect it to other standards.
Used on: large transfer pumps, tank flanges and main irrigation lines.
G2 is a BSP parallel thread of 59.614 mm major diameter at 11 TPI, cut to the 55 degree Whitworth form of ISO 228. Being parallel it seals on a washer or bonded seal at the face, not on the thread flanks.
Quick-connect click fittings from Hozelock, Gardena and Karcher are proprietary and do not interchange. They all sit on top of a standard thread underneath, so the reliable way to move between brands is to adapt at the threaded tap or hose-end fitting, then use each brand's own connector above it.
Connect this thread
Questions and answers
What is the designation of the 2" BSP parallel (G2 / BSPP) (G2)?
G2
What is the major diameter of the 2" BSP parallel (G2 / BSPP) (G2)?
59.614 mm
What is the threads per inch / pitch of the 2" BSP parallel (G2 / BSPP) (G2)?
11
What is the thread form of the 2" BSP parallel (G2 / BSPP) (G2)?
parallel, 55 degree