Choose the Klenow Fill-In Kit to perform both partial fill-in reactions to complete fill-in of a 5 overhang to generate blunt ends, and allow direct ligation. Or, use the kit to radioactively end label a 5 overhang with [alpha-32P]dNTP.The Klenow Fill-in Kit contains Klenow fragment (125 U), dNTPs (separate 10 mM stocks), Klenow reaction buffer, predigested DNA, which can be used as a control, and sufficient material for 25 reactions.