English to Slovak Tech/Engineering Electronics / Elect Eng Transformers

In the specifications for a transformer, what does a metric mounting mean? Context is here:

"has the following ratings; 400 Volt 50 Hz single phase primary, 48 KVA at a 100% duty cycle (68 KVA at a 50% duty cycle), secondary no load voltage range of 5.0 to 7.0 volts in four steps, taps changed via studs on the primary, secondary connection via machined pads, water cooled (1 GPM minimum), metric mounting, stacked core at 1.38 Tesla and fully potted..."

Thank you for help.