Our LD-FPI-SP12 is our narrowest standard leak detection sensor.  It is designed to fit into your tight interstitial space and only needs a clearance of 1 ¼”.  The stainless steel shroud protects the float from debris and protecting the float operation from being disturbed by making contact with a tank wall or other objects.  The internal components include PVC and Nylon, helping to make this sensor a high quality, low cost leak detection sensor.