Merkava Mk. 3
IDF started to use the Merkava Mk. 1 tanks in late 70's in mid 80's Merkava Mk. 2 started to enter the service with its improved fire control, armor and 60mm mortar been added. In the 90's Merkava Mk. 3 started to enter the service
Fire Control And Observation
Merkava Mk. 3A 
First model of the Merkava Mk. 3 tank
Merkava Mk. 3B
Merkava Mk. 3A with improved armor. 

Merkava Mk. 3 Baz
Merkava Mk. 3B with Knight Mk. III (Baz) advanced fire control system, from Electro Optics Industries (EL-OP) and Elbit Ltd, provides the tank with the ability to engage moving targets while on the move (an automatic target tracker), and significant improvements in ballistic protection. 

Merkava Mk. 3D
Merkava Mk. 3 Baz with fourth generation armor, additional armor plates on the chassis and the turret.
02 January 2003
The last "Merkava 3" tank to be produced, was presented today (2 Jan.) in a special ceremony held I one of the IDF's Technological and Logistics Directorate bases.
The newer model "Merkava 4" will soon be operational in the Armor Corps.
In the photo: Brig. Gen. David Angel, head of the "Merkava" project, awarding tank documents of the last "Merkava 3" tank, to a Division Commander of the Armor Corps, Lt. Col. Zafrir Orpaz.