Each manhole cover key has a different design and purpose: J-Type manhole cover keys for Recessed Trays (MC-7100 Series) and Pressed Steel (MHC-9100 Series), T-Handle for A15 Iron (MHC-5100 series) & Steel Solid Tops (MHC-9100 Series), and D-Handle for B125 Iron (MHC-6200 Series) C250 (MHC-6300 Series) D400 (MHC-6400 Series) and Block Pavior Trays (MHC-8000/8100 Series).