A composition comprising: (A) an organopolysiloxane, (B) a filler present at a concentration of 80-95 wt% of the composition weight and (C) a filler treatment agent, comprising a mixture of two organopolysiloxanes having the general formulas (I) and (II) R 1 R 2 R 3 Si-[(CH 2 ) n1 (Me 2 SiO) m1 ] r -[O-(Me 2 SiO) m3 ] p -(Me 2 Si) o (CH 2 ) n2 (Me 2 SiO) m2 -(CH 2 ) n3 -Si(OR 4 ) 3 (I) wherein 'Me' is methyl group, R 1 , R 2 and R 3 are independently selected from an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or -(OSiR 7 R 8 R 9 ), in which R 7 , R 8 and R 9 are independently selected from an alkyl group having 1 to 4 carbon atoms, R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3 and o are integers from 1 to 200, m2, n3, r and p are integers from 0 to 200, r and p are not 0 at the same time, (R 5 O) 3 Si-[(CH 2 ) n1 (Me 2 SiO) m1 ] r -(CH 2 ) n4 -[O-(Me 2 SiO) m3 ] p -(Me 2 Si)o- (CH 2 ) n2 -(Me2SiO) m 2 -(CH2) n 3 -Si(OR 6 )3 (II) wherein R 5 and R 6 are an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o and n2 are integers from 1 to 200, n3, n4, m2, r and p are integers from 0 to 200, r and p are not 0 at the same time. (A) an organopolysiloxane, (B) a filler present at a concentration of 80-95 wt% of the composition weight and (C) a filler treatment agent, comprising a mixture of two organopolysiloxanes having the general formulas (I) and (II) R 1 R 2 R 3 Si-[(CH 2 ) n1 (Me 2 SiO) m1 ] r -[O-(Me 2 SiO) m3 ] p -(Me 2 Si) o (CH 2 ) n2 (Me 2 SiO) m2 -(CH 2 ) n3 -Si(OR 4 ) 3 (I) wherein 'Me' is methyl group, R 1 , R 2 and R 3 are independently selected from an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or -(OSiR 7 R 8 R 9 ), in which R 7 , R 8 and R 9 are independently selected from an alkyl group having 1 to 4 carbon atoms, R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3 and o are integers from 1 to 200, m2, n3, r and p are integers from 0 to 200, r and p are not 0 at the same time, (R 5 O) 3 Si-[(CH 2 ) n1 (Me 2 SiO) m1 ] r -(CH 2 ) n4 -[O-(Me 2 SiO) m3 ] p -(Me 2 Si)o- (CH 2 ) n2 -(Me2SiO) m 2 -(CH2) n 3 -Si(OR 6 )3 (II) wherein R 5 and R 6 are an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o and n2 are integers from 1 to 200, n3, n4, m2, r and p are integers from 0 to 200, r and p are not 0 at the same time. wherein 'Me' is methyl group, R 1 , R 2 and R 3 are independently selected from an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or -(OSiR 7 R 8 R 9 ), in which R 7 , R 8 and R 9 are independently selected from an alkyl group having 1 to 4 carbon atoms, R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3 and o are integers from 1 to 200, m2, n3, r and p are integers from 0 to 200, r and p are not 0 at the same time, (R 5 O) 3 Si-[(CH 2 ) n1 (Me 2 SiO) m1 ] r -(CH 2 ) n4 -[O-(Me 2 SiO) m3 ] p -(Me 2 Si)o- (CH 2 ) n2 -(Me2SiO) m 2 -(CH2) n 3 -Si(OR 6 )3 (II) wherein R 5 and R 6 are an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o and n2 are integers from 1 to 200, n3, n4, m2, r and p are integers from 0 to 200, r and p are not 0 at the same time. <EOS>