This mech paper model is Howler (Baboon), first observed among Clan Jade Falcon second-line units, though it has since been proven to be much more widespread, from the game Classic BattleTech, the papercraft is created by Yogsolthan. The size of finished model is about 181 (H) x 120 (W) x 84 (D) mm.
The BattleMech the Inner Sphere dubbed the Baboon is moderately fast for a 'Mech its size, topping out at 119 km/h. Its armament is at least partially enabled by the use of an Endo Steelstructure and three tons of Ferro-Fibrous armor.
You can download the papercraft model here: Classic BattleTech - Howler (Baboon) Free Mech Paper Model Download