A bottle closure assembly comprising: an integrally molded: cap portion, elongated tether portion, and retaining means portion; the cap portion being molded to reversibly engage and cover a bottle opening, the retaining means portion being molded to irreversibly engage a bottle neck or an upper portion of a bottle, and the elongated tether portion being molded to connect at least one point on the cap portion to at least one point on the retaining means portion; wherein the integrally molded: cap portion, elongated tether portion and retaining means portion are made from a polyethylene composition comprising: 10 to 70 wt% of a first ethylene copolymer having a melt index I 2, of 10 g/10min or less; and a density of from 0.920 to 0.960 g/cm 3; and 90 to 30 wt% of a second ethylene copolymer having a melt index I 2, of at least 50 g/10min; and a density higher than the density of the first ethylene copolymer, but less than 0.970 g/cm 3; wherein the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in said first ethylene copolymer to the number of short chain branches per thousand carbon atoms in said second ethylene copolymer is greater than 0.5; wherein the polyethylene composition has a tensile strength at break of at least 16 MPa; and wherein an elongated tether has a length which is greater than its width and/or height/thickness. an integrally molded: cap portion, elongated tether portion, and retaining means portion; the cap portion being molded to reversibly engage and cover a bottle opening, the retaining means portion being molded to irreversibly engage a bottle neck or an upper portion of a bottle, and the elongated tether portion being molded to connect at least one point on the cap portion to at least one point on the retaining means portion; wherein the integrally molded: cap portion, elongated tether portion and retaining means portion are made from a polyethylene composition comprising: 10 to 70 wt% of a first ethylene copolymer having a melt index I 2, of 10 g/10min or less; and a density of from 0.920 to 0.960 g/cm 3; and 90 to 30 wt% of a second ethylene copolymer having a melt index I 2, of at least 50 g/10min; and a density higher than the density of the first ethylene copolymer, but less than 0.970 g/cm 3; wherein the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in said first ethylene copolymer to the number of short chain branches per thousand carbon atoms in said second ethylene copolymer is greater than 0.5; 10 to 70 wt% of a first ethylene copolymer having a melt index I 2, of 10 g/10min or less; and a density of from 0.920 to 0.960 g/cm 3; and 90 to 30 wt% of a second ethylene copolymer having a melt index I 2, of at least 50 g/10min; and a density higher than the density of the first ethylene copolymer, but less than 0.970 g/cm 3; wherein the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in said first ethylene copolymer to the number of short chain branches per thousand carbon atoms in said second ethylene copolymer is greater than 0.5; wherein the polyethylene composition has a tensile strength at break of at least 16 MPa; and wherein an elongated tether has a length which is greater than its width and/or height/thickness.