Trumpeter 1/35 Trumpeter USA Mk23 MTVR MAS Armor System (Medium Tactical Vehicle Replacement)Description Medium Tactical Vehicle Replacement (MTVR) is a six wheel drive all terrain vehicle used by the USMC and US Navy. It is designed to replace the old M939 tactical trucks, and was first fielded in 1998, after the contract was awarded to Oshkosh Truck Corporation. The MTVR comes in several variants, for a wide spectrum of tasks. It offers a major improvement in off road capability. The MTVR Armor System (MAS) was designed for the 7 ton MTVR.