Scarce dated variety, as opposed to the more common "1876-1900" undated variety.  These have "Rattanakosin" dates, i.e. 123, etc., on the bottom of the reverse, which correspond to the number of years since the founding of the Chakri dynasty in 1781 under the first King of that dynasty, Rama One.  This one corresponds to 1904.  These were only struck with dates for a handful of years from 1901 to 1907

Honest wear on this silver coin with about the same actual silver content as a heavy U.S. half dollar of the same era.  Graded Very Fine 30 -  by Numismatic Guarantee Corporation.  Most of these coins have problems like cleaning or other damage.  This one does not.  It is just honest worn.