This Monument set of 6 Test Plugs contains the following small bore test plugs:
2 x 1370B 15mm Test Plugs.
2 x 1371E 22mm Test Plugs.
2 x 1372H 28mm Test Plugs.

The plugs are used for blocking off small pipes such as copper pipes for dry testing prior to commissioning, however they cannot be used for air testing purposes by themselves.