Land Rover Series 3 Stage 1, 90, 110, Range Rover Classic.

Durite/Smiths Oil Pressure Gauge Oil Capillary Hose T Piece Adapter

BZP (Bright Zinc Plated adaptor has dual inlets, one for the standard oil pressure switch and one for the oil pressure gauge

The block and oil pressure switch are 1/2" UNF

Hoses etc NOT included  the side arm is 1/8 BSP (also accepts 1/8 NPT).