The difference between the blood pressure at the wrist and the arm is usually normal.
BP Monitor - NHS Supplied Blood Pressure Monitor / BP Machine UK Health
BP Monitor - NHS Supplied Blood Pressure Monitor / BP Machine UK Health for Home
OMRON X2 Basic Automatic Upper Arm Blood Pressure Monitor for Home Use - Clinically Validated BP Monitor with Irregular Heartbeat Detection - BP Machine with BP Cuff 22-32 cm - Batteries Included
OMRON RS3 Intelli IT Wrist Blood Pressure Monitor for Home Use or on the Go - Clinically Validated Wrist Blood Pressure Machine with Free Smartphone App - Wrist BP Monitor with BP Cuff and 30 Readings