The 35mm unit is 640 resolution. That is a SMOKING good deal on it. The 19mm unit is lower resolution.

Description of the unit from the TNVC website:

The FLIR LS-Series is the Law Enforcement version of the Commercial PS-Series. Compact and handy, the LS-Series is about the size of an AN/PVS-14 and gives officers the ability to see in absolute pitch black conditions because it is a thermal imaging device that detects heat produced by people, animals, vehicles, etc, rather than amplifying light. Thermal is one of the most effective night vision tools for detecting possible threats because it can see through smoke, dust, light fog, snow falling, and rain. It causes heat-producing objects to stand out against cooler backgrounds, giving bad guys less places to hide.

The LS-Series is a higher-performing version of the Scout PS-Series, designed for professionals, but available to civilians as well. These units feature higher resolution than their commercial counterparts and in integrated laser pointer. The laser is good for pointing out suspects to other officers who do not have night vision or thermal aid. Lightweight and rugged, the LS units fit in the palm of your hand. Its housing has been designed with ergonomics in mind, utilizing simple and intuitive controls. The sleek body housing allows it to easily slip in and out of coat pockets and vest pouches without snagging. A single focus knob can be actuated one-handed.

The LS-XR is the higher-resolution variant of the LS-Series, featuring a 640×512 detector, 35mm lens, and 4x Electronic Zoom.

The LS-Series uses an internal, rechargeable battery that requires the unit to be plugged into a power source for charging. Batteries cannot be replaced in the field. If anything, this is the one drawback to the system because a fully-charged unit will have about 5 hours of battery life. The FLIR LS-Series is a great option for law enforcement officers and civilians who want a highly-portable, lightweight, yet powerful thermal imaging device.