6.25 in L x 5 in W
They are stamped on the left side with their brand and engraved on the right side with the letters, "MG."
Hunsicker & Alexis, based in Paris, were renowned optical instrument makers during the early 20th century. They supplied precision optics to the French Ministry of War and the British War Office during WWI. The engraved MG stands for Ministere de la Guerra, aka French Ministry of War.
When looking through the lens, it appears that the right lens is cracked. It is difficult to focus and thus these are more of a decorative item unless you know how to restore them.