ESO Fuse insert/Extractor. Schurter Fuse Inserter, extractor and cover is suitable for CSO fuse clips and 10.3 x 38mm fuses. The ESO can be used to insert and extract fuses from the fuse clips. The ESO can also be used as a fuse cover offering touch safe IP20 protection. Applications include: All Photovoltaic applications. Inverters. Battery charge controllers. String fuses. DC applications.