[7] The YAK is an upgraded, ballistic and mine-protected, variant of the DURO IIIP 6x6 chassis used by the German Army.

The actual contract covered the supply of 100 Yak chassis and a total of 114 bodies in the following configurations: 31 × mobile medical team; 8 × prisoner transport; 6 × water cannon; 23 × command post for military police; 23 × air base security; 2 × military geography; 21 × explosive ordnance disposal.

[8][9] In 2008, RMMV delivered three armoured NBC field laboratories to the Swiss Army which are similar to the Yak.

[9] The 420 Duro GMTF ordered by the Swiss Army are equipped with a Protector RWS and a diesel engine Cummins ISB5-9 (275 hp).

Robur and Duro have similar exterior dimensions, therefore existing fire houses required no structural alterations for new vehicles.

The conversion failed due to the purchase price of Duro, which exceeded the financial strength of the fire departments.

The Singapore Civil Defence Force uses the LFAV, a vehicle based on the chassis of the Duro, the Red Rhino [11][12].