telescoping pole locking mechanism

US NFPA 72 quarterly residential smoke detector testing direct from Wanlin Fire Protection — 12-year factory experience, WL-ST300 smoke detector tester certified CE/UL 268A/EN 54/NFPA 72/BS 5839/AS 1851. Key specs: Aerosol Dispersion + Bluetooth 5.0 + Mobile APP + Data Logging + Test Report Generation, Bluetooth 5.0 + Mobile APP (iOS/Android) + Test Data Sto···