block and tackle
device consisting of two pulleys (or in a borderline case only one movable pulley); device multiplying force; machine used to lift heavy loads
en-US/ˈblɑk ˈænd ˈtækəl/
en-GB/ˈblɒk ən ˈtækl/
device consisting of two pulleys (or in a borderline case only one movable pulley); device multiplying force; machine used to lift heavy loads