1. Used to sense the change of flow that passes the pipe lines, playing a role to protect the torrential flow. 2. Can be regulated based upon different run-off of flow. 3. Employ a SPDT miniature switch with large capacity, possessing the advantages of quick action to guarantee the transient of the switch. 4. The housing applies the totally enclosed construction ensuring switch's normal work under any circumstances. 5. Liquid temperature 0 to 120 deg. celsius.