Item Type: 2 Way Voice Intercom Model: H9 Material: ABS Battery: Rechargeable lithium battery 3.7V 1000mAh, with built in battery. Use: Widely used in household, office, laboratory, treatment, etc. Working Temperature: -20 ~55 Transmission Distance: 100 meters in open are, and 5-20 meters with wall. Package List 2 x Internal Unit 1 x External Unit 1 x USB Cable 1 x Screwdriver 1 x User Manual 1Great Workmanship: High gloss surface, good touch of buttons, internal waterproof design, with intercom light and battery light display, so you can easily understand it at a glance. 22 Way Communication: Supports 2 way audio, nursing pagers are suitable for caregivers and patients, elderly, residents, disabled to freely seek help while still at home. No need to shout to attract others' attention. 3Low Power Consumption: Adopting intelligent power saving chips, it can be used for more than six months under normal status after being fully charged, and it does not work normally and never consumes electricity. 4Easy to Operate: Large and adjustable speaker with clear sound, can be used as a mobile intercom, which will bring more convenient to your daily life. 5Smart Matching: The outdoor doorbell and indoor doorbell are paired through learning code, and one outdoor doorbell can be paired with two indoor doorbells without interfering with each other.