I have found a photograph of my grandfather Janos Tokos and his brother Martin from Holic (Slovokia)in their WW1 uniforms. My grandfather has a numeral 4 on his collar while his brother has a 301 on his collar. My grandfather also has a chevron on his lower left sleeve.

Can anyone identify the type of uniform and military unit of my grandfather and his brother.

Not regular Austro-Hungarian army. Can you scan or use a magnifying glass on the cap badge?

Maybe a local para-military or nationalist organization. Also possibly post-WWI in the new Czech republic.

The cap badge might have an important clue.

Mark, I am not sure that I agrre that it is not an Austro-Hungary Army uniform. There is information in the family that the brothers served in the army and no indication of membership in a local para-military or nationalist organization. They lived in Holic (CZ) now Slovakia. I have attached a file with the hat insignia. - it may help. The collar numerals "4" and "301" are what I have focused on to hopefully identify a unit. IR72 would have been their local army unit. Al,

Austro-Hungarian WWI uniforms are recognizable by their scalloped breast pockets. So that fits with your picture. But what does not fit are the numbers on their collars. The rank of the soldier was indicated on the collars. If you go to the following website:
http://przemysl.blogspot.com/2006_12_01_archive.html
And go down about 2/3s of the site, you will find a whole section on the army uniforms and the collars for each rank. But none contain numbers. So, these uniforms are puzzling. All kinds of caps were used by the soldiers and in some cases they were allowed to buy and wear special ones of their own.
I did look to see if it might have been a honved uniform but again, they didn't have numbers on the collars either.
CK

I agree. The clothing is Austro-Hungarian, certainly in style if not in actual origin. But the caps and collar patches are just not any KuK style known to me (which I admit, could be a pretty big gap).

What's odd is that this very unusual uniform is apparently in two units: the "4th" and the "301st". They must be under the same overarching organization. Also, in regular European armies the numeral 301 is a fairly rarified beast. You have to have a pretty large armed force to have to count all the way up to 301. It makes me think it designates something small, like a local homeguard platoon or political party's district office. Just speculating.

Mark,
I guess it is one step at a time. On the lower right sleeve is a chevron. Do you have any idea what this represents - wounded? I have knowledge that my grandfather fought on the italian front and was a POW - this was passed to my parents - I could have gotten the information first hand but who thought about it. Al,

Al,
The soldiers did not belong to the AH common army or the Hungarian Honvéd army when the photo was taken. I think it was taken right after WWI, in time of forming the new state/army of Czechoslovakia. That's why you can identify the AH style clothing, but the badges are already changed.
Of course it does not exclude the possibility that they served in the AH army during the war (IR72 or Honvéd IR13).
Is there anything on the back-side of the picture? (The name of the town could prove if the photo was taken after the state change)
Br
Laszlo