A polymer composition comprising a blend of two or more high density polyethylenes: (A) a first high density polyethylene having a density of at least 940 kg/m3 and an MFR2 of 0.25 g/10 min or less; and (B) a second high density polyethylene having a density of at least 940 kg/m3 and an MFR2 of 1.0 g/10 min to 20 g/10 min; wherein said polymer composition has an MFR2 of 0.25 to 15 g/10 min and wherein the components (A) and (B) combined form at least 91 wt % of said polymer composition.