T-PIECE COMPRESSION FITTING CONNECTOR 15mm - YOUR INLINE 15mm to accumulator and pump etc
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15mm COPPER COMPRESSION FITTING to 1/4" BSP FEMALE THREAD ADAPTOR PIPE FITTING
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1/4"NPT Male to 1/4"Bsp Male Adaptor
Pressure switch 1/4" NPT

https://www.amazon.co.uk/dp/B00Q5UB26K/