I wish to fit a Protector system which I can purchase. Where you say refine search, I put in from the information plate the Manufacturer, CHAMBERLAIN & exact model No. 420EGB, there are no more manufacturers names or model No's. so can you please give me an idea what an unknown piece of kit that seems to be a one off that your good selves and Chamberlain USA say Zero finds for it . Peter Woolhouse, email: jelly807-burridge@yahoo.co.uk.