A circuit includes a complementary current mode logic driver circuit and a dual feedback current mode logic bias circuit. The motor control is by a first controllable switching device to connect the battery to the motor with a first polarity to cause the plant to move in a first direction, or a second controllable switching device to connect the battery to the motor with a second polarity opposite the first polarity to cause the plant to move in a second direction. The bolt which is adapted to be removably connected to a second structural member has an intermediate portion provided with a plurality of circumferential sealing lips.