they were archers using both the right and left hands to sling stones and shoot arrows; and they were Saul’s kinsmen from Benjamin):
KJV
[They were] armed with bows, and could use both the right hand and the left in [hurling] stones and [shooting] arrows out of a bow, [even] of Saul’s brethren of Benjamin.
ASV
They were armed with bows, and could use both the right hand and the left in slinging stones and in shooting arrows from the bow: they were of Saul’s brethren of Benjamin.