The 1277S - Monument - 1m Rubber Tube is a specific replacement hose for gas test gauges used by plumbing and heating professionals in the UK. 
Product Specifications
Manufacturer: Monument Tools.
Length: 1 metre.
Material: Black Nitrile rubber.
Internal Diameter (ID): 7/32 inch (5.5mm).
Application: Primarily used with manometers and U-gauges for standard gas pressure testing.
Important Note: This hose is not suitable for use with LPG (low pressure gas)applications.