These 4K DVRs make evidence collection a snap. Get 4K crystal clear video recorded by hidden cameras built into ordinary household and office devices. Record video to a removable memory card. Onboard storage means your evidence is less likely to be hacked online. Zone Shield DVRs are built into AC powered devices so you never worry about battery life. Xtreme Life DVRs are built into long life battery powered devices so your camera can go indoors, outdoors, and anywhere a power cord can't reach.