... of the customer,convenient installment.4 Black and yellow,affect in day and night,attack the attention of the ... ,highroad crossing,toll gate,garden,village,parking lot,and gas station,etc.Instructions:1) Speed bumps can ... be installed on the surface of asphalt roads and concrete roads.2) To improve life span , ... After drilling,clean up the holes and remove the dust,oil and debris from the holes.Using the ...