Edison Electric Illuminating Company of Boston's work is atop this cool piece of architecture. A scattering of this type of construction still exists in older neighborhoods within the former Boston Edison system where the primary voltage is 4kv. Beneath is a sampling of what the Boston Fire Department alarm openwire looked like. This four-pin crossarm is mounted via two lag-bolts. Many Standard Glass signal insulators were employed along Boston's Fire Alarm circuits. All of their crossarms were painted white with "Fire Alarm" stenciled in black paint so they could be easily identified.