Three-character transliteration:
汉 'han' renders 'Han-' (the 'h' onset is preserved),
克 'ke' renders the '-nk' cluster,
斯 'si' renders the '-s' ending.
斯 is the all-purpose ending for English '-s' final names:
詹姆斯 James,
道格拉斯 Douglas,
戴维斯 Davis. The leading
汉 is also the character for 'Han Chinese / Han dynasty', which is purely coincidental here.