The Israel Defense Forces still operates large numbers of the M113, maintaining a fleet of 6,000 of the vehicles. On numerous occasions since their introduction in the late 1960s, the IDF's M113s have proven vulnerable to modern anti-tank missiles, IEDs, and RPGs, resulting in the deaths of many Israeli soldiers riding inside the vehicles. The IDF has nonetheless been unable to replace the use of them in combat operations, due to budget constraints in equipping its large mechanized infantry regiments. Israel is also prototyping the Eitan (Hebrew for steadfast), an eight-wheeled armored fighting vehicle to replace their M113s. Designed to serve alongside the tracked Namer, the Eitan is planned to be cheaper and lighter, at 35 tons, incorporating an active protection system and a turret. They are expected to begin replacing the M113 starting in 2020. However, due to the slow rate of production of replacement APCs, the IDF is expected to be dependent on the M113 well into the 2020s. The IDF has also increased production of Namer APCs to replace the M113.