Can I use these low cost wireless security cams listed in ebay simultaneously without interference?

["owner" <wildlilysale@xxxxxxxxx>]

I want to buy 4 such cams as shown on ebay:
http://cgi.ebay.com/1-WIRELESS-PINHOLE-SECURITY-SPY-CAMERA-VIDEO-NANNY-CAM_W0QQitemZ5851990626QQcategoryZ48632QQrdZ1QQcmdZViewItem

http://cgi.ebay.com/NEW-WIRELESS-NIGHT-VISION-SPY-CAM-SECURITY-COLOR-CAMERA_W0QQitemZ5851943594QQcategoryZ48632QQrdZ1QQcmdZViewItem

I want to know can I use 4 such cams same time without inteference, ie.
each cam has different frequency and 4 cams show 4 views. None of the
ebay sellers replied my question. Please inform me if you have used
such cams simultaneously as security cams for a property.