For those looking at what era these are, these look like they are probably 1990-early 2000's
Up to the 70's - black or red A arm, mechanical bell, standard lights. Single or dual counter weights.
80's red A or bar arm, dual or single counter weight.mechanical bell. Standard lights
90's-2000 red bar arm, single counter weight mechanical bell. Standard lights
2010+ red bar arm, single counter weight, electric bell, bug eye LED lights.