Also, this could be used after drilling out a hole for a Pressure Gauge to be fitted (it would however be a bit crowded on top of the boiler!). See our listing for the Pressure Gauge.
Helpful note: With the greatest respect, if you don't know what to do with this, then may I suggest it is not for you at this time. This carrys our normal no-quibble guarantee so you can buy with complete confidence. If you are in doubt about anything in connection with this item or the model it is intended for, why not email us with your question before you make your purchase. We will be very happy to help you - and we always respond quickly!