The Royal Artillery Association was set up in 1920 to provide support to former and serving members of the regiment. The Royal Artillery was one of the largest regiments in the Army during World War One and so the association soon had a particularly large membership. To identify members of the association, lapel badges were available to be worn with civilian dress and it is one of these we are looking at today:

There are a number of different badges that seem to have been in use at various times, with and without the enamel and with or without the background voided. This example seems to be particularly common and has a crowned cannon with the letters of the association on a red ground and then surrounded by a blue band with the regiment’s mottos on it.
The rear of the badge has a standard crescent shaped lapel stud to allow it to be worn in the lapel button hole of a jacket:

These old comrade lapel badges have become increasingly popular over the years, although this is one of the easiest to find- largely due to the large size of the regiment and consequently the large numbers of the badge orignally produced.