Clamp, V-band, 4.50" outer diameter (same as one used on GT42R compressor outlet 3.5" v-band flange)
Heavy Duty Stainless Steel V-Band Clamp, 4.50" diameter, same one used on GT42 compressor outlet 3.5" v-band flange. 3.5" refers to the tube diameter (inner edge) used with the V-band flange. 4.5" refers to the outer diameter (outer edge) of the v-band flange itself.