The 3.7inch howitzer was introduced in 1917 and deigned to be transported by pack animals.

3.7in QF Mountain Howitzer 

It would see action in Palestine, Mesopotamia, East Africa, and post Armistice, in Russia and on the North West Frontier of India.

3. 7 inch mountain howitzers on pack mules, Sadleir-Jackson Brigade, Troitsa, 1919.

The mountain howitzer broke down in to eight mule loads. Additional mules carried ammunition, gun stores, signalling equipment, with spare and relief mules also part of a Mountain Battery's order of battle.

3. 7 inch mountain howitzers on pack mules - Wheel and Axle Mule

3. 7 inch mountain howitzers on pack mules - Trail, front part Mule

3. 7 inch mountain howitzers on pack mules - Pivot Mule

3. 7 inch mountain howitzers on pack mules - .Cradle Mule

3. 7 inch mountain howitzers on pack mules - Slipper Mule

3. 7 inch mountain howitzers on pack mules - Trail, rear part Mule

3. 7 inch mountain howitzers on pack mules - Breech Mule

3. 7 inch mountain howitzers on pack mules - Chase Mule

3. 7 inch mountain howitzers on pack mules - Shield Mule

3. 7 inch mountain howitzers on pack mules - Ammunition Mule