A liquid curable silicone elastomer composition comprising • an organopolysiloxane comprising ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 0.01 to 1.5 mmol/g, and ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 5.0 to 15.0 mmol/g; • an organopolysiloxane comprising ∘ organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (R 2 HSiO 1/2) x where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and x ≥ 2; and ∘ optional organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (RHSiO 2/2) z where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and z ≥ 2, o wherein the molar amount of silicon-bonded hydrogen in the form of siloxy units of the type (R 2 HSiO 1/2) x is >40mol% of the total silicon-bonded hydrogen atoms content of organopolysiloxane; • a platinum based catalyst; • an inhibitor selected from the group consisting of acetylenic alcohols and their derivatives; • a silica filler; characterised in that a hardness of > 75 Shore A without post cure is achieved in the resulting cured silicone rubber measured using ASTM D2240-15. • an organopolysiloxane comprising ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 0.01 to 1.5 mmol/g, and ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 5.0 to 15.0 mmol/g; ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 0.01 to 1.5 mmol/g, and ∘ organopolysiloxane containing at least 2 alkenyl groups bonded to silicon atom per molecule and having a total alkenyl content of from 5.0 to 15.0 mmol/g; • an organopolysiloxane comprising ∘ organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (R 2 HSiO 1/2) x where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and x ≥ 2; and ∘ optional organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (RHSiO 2/2) z where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and z ≥ 2, o wherein the molar amount of silicon-bonded hydrogen in the form of siloxy units of the type (R 2 HSiO 1/2) x is >40mol% of the total silicon-bonded hydrogen atoms content of organopolysiloxane; ∘ organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (R 2 HSiO 1/2) x where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and x ≥ 2; and ∘ optional organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms per molecule, wherein said silicon-bonded hydrogen atoms are provided in the form of siloxy units of the type (RHSiO 2/2) z where R is independently selected from hydrogen, aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group and z ≥ 2, o wherein the molar amount of silicon-bonded hydrogen in the form of siloxy units of the type (R 2 HSiO 1/2) x is >40mol% of the total silicon-bonded hydrogen atoms content of organopolysiloxane; • a platinum based catalyst; • an inhibitor selected from the group consisting of acetylenic alcohols and their derivatives; • a silica filler; characterised in that a hardness of > 75 Shore A without post cure is achieved in the resulting cured silicone rubber measured using ASTM D2240-15.