21
under the article in question.
11. Technical characteristics
Supply voltage: 3V
Batteries: 2x LR03 (micro/AAA)
Battery life: 5 years approx.
Receiver frequency: 868.3MHz
Receiver class: SRD Class 2
Typical open air range: 100m
Housing dimensions (WxHxD)
Electronic unit: 18.5x103.5x24.5mm
Magnet: 12x48x12mm