The GMP Tools External Circlip, 20 mm (part 32217, Millennium part 526752), retains shafts and bearings in place on GMP cable blower systems, keeping rotating components from shifting during jetting operations. Techs replace this small retaining ring when the factory circlip loses tension or is lost during a rebuild. It's a routine spare parts item for keeping blower internals properly assembled in the field. Stock it with related guide cable assemblies and seloc pins for the same GMP equipment.