PositiveElectrical

Hi was wondering if anyone could help me. I wanted to fit a wireless CCTV system into one of my customers house, as they have had a lot of robberies in the area. Wanted a 4 camera system with a DVR and maybe even the option to log in via phone. It is a medium detached house, and each camera would need a maximum of 15m range. I would be grateful is anyone could help recommend a system that they know works well and has good facail recon, even at night? Thanks guys.