The REDARC 2.5″ Muffler Clamp has a maximum of 2.5″ (36-63mm) opening. It has been designed to mount the REDARC EGT probe.
The GMC-2.5 is an optional accessory that is compatible with the following REDARC gauges: G52-BEP, G52-BET. G52-BEA, G52-EB and G52-EU.
Manual available here: GMC Instruction Manual