These were called EU models or some such. There are larger and smaller versions. They are rarer birds.
Modified from the ergo handled models. The one pictured would be a Battlemistress Ergo variant, possibly a zero tolerance ergo battle mistress blank.
The EU-17 models. "Extraction Unit"
"These knives were offered in regular, magnum and mini sizes. They were made from E-series blades, specifically the BM, SH, and either NO or BA"