A high-volume sprinkler head comprising: a barrel (12, 14) having a nozzle at one end thereof, said barrel having a fixed portion and a relatively movable portion adapted for pivoting movement relative to said fixed portion, said barrel mounted on an annular upper support base rotatably supported on a lower stationary base for rotation in opposite directions through an arc about a substantially vertical axis; an actuator arranged to pivot said relatively movable portion of said barrel relative to said fixed portion of said barrel between predetermined first and second reaction angles that cause said barrel and said annular upper support base to rotate in opposite directions, about said substantially vertical axis, respectively, when a stream is emitted from said nozzle; the high-volume sprinkler head being characterized in that it further comprises: first and second magnets (70, 72) supported at circumferentially-spaced locations about an edge of said lower stationary base, said pair of magnets having opposite polarities; and a magnetic valve mounted on said upper support base in fluid communication with said actuator, said magnetic valve adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined first reaction angle when said magnetic valve is proximate to said first magnet, and further adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined second reaction angle when said magnetic valve is proximate to said second magnet. a barrel (12, 14) having a nozzle at one end thereof, said barrel having a fixed portion and a relatively movable portion adapted for pivoting movement relative to said fixed portion, said barrel mounted on an annular upper support base rotatably supported on a lower stationary base for rotation in opposite directions through an arc about a substantially vertical axis; an actuator arranged to pivot said relatively movable portion of said barrel relative to said fixed portion of said barrel between predetermined first and second reaction angles that cause said barrel and said annular upper support base to rotate in opposite directions, about said substantially vertical axis, respectively, when a stream is emitted from said nozzle; the high-volume sprinkler head being characterized in that it further comprises: first and second magnets (70, 72) supported at circumferentially-spaced locations about an edge of said lower stationary base, said pair of magnets having opposite polarities; and a magnetic valve mounted on said upper support base in fluid communication with said actuator, said magnetic valve adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined first reaction angle when said magnetic valve is proximate to said first magnet, and further adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined second reaction angle when said magnetic valve is proximate to said second magnet. first and second magnets (70, 72) supported at circumferentially-spaced locations about an edge of said lower stationary base, said pair of magnets having opposite polarities; and a magnetic valve mounted on said upper support base in fluid communication with said actuator, said magnetic valve adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined first reaction angle when said magnetic valve is proximate to said first magnet, and further adapted to cause fluid to propel said actuator to move said movable barrel portion to said predetermined second reaction angle when said magnetic valve is proximate to said second magnet.