Earlier releases had suggested that Germany offered 15 Leopard 2A4 MBTs to Slovakia, in exchange for 30 T-72 main battle tanks that Bratislava was to transfer to Ukraine. The Slovaks were not satisfied with the said offer, as, as they argued, it would have a detrimental impact on the combat capabilities of the Slovak Armed Forces. Bratislava wanted to have enough tanks at its disposal, to equip a single battalion of no less than 30 vehicles.
The agreement that the Parties have ultimately reached assumes that Slovakia would only receive 15 German main battle tanks, meanwhile, it would transfer the reserve BVP-1 IFVs to Ukraine (instead of the T-72 MBTs). The BVP-1 is a licensed-manufactured, Czechoslovak variant of the Soviet-made BMP-1 vehicle. Maybe the Slovaks concluded that in the light of the CV-90 procurement they are making, a solution as such would not have a major detrimental impact on the combat capabilities.
Germany has been endorsing its “Ringtausch” concept for quite some time now, assuming that equipment exchange is happening between NATO allies, having Berlin transfer western-made equipment to the allies who decide to transfer their post-Soviet systems to Ukraine. This scheme has probably been used by the Czech Republic, with a transfer of 20 T-72 main battle tanks (from the reserve units stockpile) to Ukraine happening in exchange for 15 Leopard 2A4 MBTs taken out of the German industrial stockpile.
The very same source would be used to transfer main battle tanks to Slovakia, as the Bundeswehr has no Leopard 2A4 MBTs of its own. In the case of the Czech Republic, this is viewed as a prelude to the introduction of a greater number of newly and jointly manufactured Leopard 2A7 MBTs in the Czech Army. It remains an open question whether Slovakia also decides to procure more German-made main battle tanks.
The “armoured exchange” offer has also been placed in Poland. Warsaw, however, was only offered 20 Leopard 2A4, 100 legacy Leopard 1A5, or brand new main battle tanks. Poland expected Germany to transfer at least 44 Leopard MBTs, in exchange for the MBTs already handed off to Ukraine - that number would be sufficient to equip at least a single tank battalion. Germany is reserved when it comes to a direct transfer of its main battle tanks to Ukraine - even when it comes to the industrial stock of the Leopard 1A5 vehicles - being worried about such a move being interpreted as an escalation.