Series F6 & F7 Horizontal Mount Level Switches are designed to mount through the walls of tanks and other vessels. Internally mounted models F6-HPS-11, F6-MHS and F7-SS5 are secured to the wall of the tank or vessel from the inside while model F6-HPS-21 is mounted from the outside (externally). Model F7-HSS can be installed internally or externally.Series F6 & F7 Specialty Level Switches are designed for unique applications. Model F7-SS5B/BNC can be used with viscous liquids or liquids with suspended metal particles. Use model F7-LL for low level detection (≥5/8″). The non-intrusive bottle style F7-EB mounts completely outside the tank at the actuation level. Suspend model F7-WBB in stand pipes or sumps for leak detection or drop into wells for ground-water monitoring.