This bronze dagger was found in a tomb (numbered 1502) in the ruin mound of the ancient city of Lakish (Tell ed-Duweir or Tel Lakhish, "Lachish), and it is tentatively dated around 1600 BCE.
The inscribed characters are pictorial, and so they presumably belong to the earliest period of the proto-alphabet.
Reading from the top, there is a curved line, which could perhaps be a letter, but it is very problematic.
The oval with two verical strokes at one end would be an example of a tied bag, and thus Sadey (Ss or S.) according to my table of signs. As nobody else acknowledges this connection, my reading of the inscription is unique.
The human head is indubitably R (its Hebrew name is still Rosh, meaning "head"); everyone agrees on this.
The snake always represents N (from nakhash "snake"). Here it is a horned viper, though the erect cobra is more usual, and is the origin of N.
The last letter is like a telegraph pole, with two crossbars (though a set of three is also found, and the original was a stylized spinal column (the Egyptian djed column). This is S (Samek), but the fish-sign was an alternative letter for Samek in the beginning.
S. R N S
The many attempts at reading the inscription see it as the name of the owner, but he is given a string of aliases, as the various scholars all come up with something different.
Looking at the context, this weapon would presumably be in the tomb with its owner as a defence against the powers of evil in the world of the afterlife.
Accordingly it divides up neatly into two words of command (vocative case and imperative mood, we might say):
S.R NS "Foe flee"
Brian E. Colless, The proto-alphabetic inscriptions of Canaan, Abr-Nahrain 29 (1991) 18-66, particularly 35-36.
For a clearer photograph, see Benjamin Sass, The Genesis of the Alphabet (Wiesbaden 1988) Figure 141.