KTH17B Max input DC voltage DC52V Max input circuit Current DC 65mA Feed voltage DC48V Bell ringing voltage DC24-48V Net Weight (kg) 1.65kg Size (mm) 285mmÃ?175mmÃ?135mm Communication Distance â?¤5km,model: MHYV1*2*7/0.37 Belling Grade â?¥80dB Material ABS Protection Level IP54 Installation Wall Mounting/ desk top Link coupler KTA16B safe coupler, connect to 10 phones Dial model DTMF Function Explosion proof /waterproof/ anti-dust /anti-corrosion -