That's a neat-looking coin. I really like the design on the reverse side. I don't know what it is, but I like it!
Czechoslovakia minted 20, 25, and 50 haleru coins with lions on the front and neat patterns on the back between 1921 and 1953. The earlier dates were minted in bronze (like our primary picture), and copper-nickel (like our secondary pictures), and the later dates were minted in aluminum. As you can see, the creative designs on the backs of the 20 and 50 haleru gave way to a simple BIG 25 on the back of the 25 haleru. The 25 haleru coins were minted only in 1932 and 1933
Unless you can find one of the more rare dates listed below, all these coins are worth almost nothing. Catalog values are all below $1 US dollar except in fully uncirculated condition, which brings the catalog value up to $2 or $3.
Here are the *good dates* of the series. The dollar figures after the dates are catalog values for coins in well preserved condition. Coins in poorer condition are worth much less.
1932: (are you ready?) $2200
BTW, the catalog says the patterns on the back of the 20 and 50 halerus are linden trees.