This is a USED Quick Change Center Section Side Bell. It is a Magnesium. It is a Benson RH71.
Quickchange Center Section Side Bell WINTERS 1663-02 Alum IMCA UMP WISSOTA K&N
Quickchange Center Section Halibrand 201 Side Bell Alum Sprint IMCA Model A RAT
Quickchange Center Section Halibrand 201 Side Bell Alum Sprint IMCA Model A RAT2
Quickchange Center Section Halibrand 201 Side Bell Magn Sprint IMCA Model A RAT3
Quickchange Center Section Halibrand 301W Aluminum Sprint IMCA Model A RAT #2
Quickchange Center Section Halibrand 201 Lower Shaft 12 3/8" Alum Sprint IMCA