Armasight has accomplished what HMT users have been asking FLIR to do for years.  A small, lightweight 640 HMT with an affordable price tag.   If you have been wanting to jump up to a 640 core thermal for a HMT without breaking the bank, the Sidekick 640 should definitely be in your list of choices to consider. 
 
The Sidekick 640 is the smallest fully multi-functional 12-micron 640 thermal imaging monocular on the market. This unit boasts a fast 60Hz frame rate for smooth operation based on Armasight’s Iron Wolf thermal technology platform. Weighing under 250 grams, the Sidekick can be used as a handheld mini-monocular or can be headset/helmet mounted utilizing the built-in mini-rail for hands-free operation. The high definition 1024×768 OLED display provides vivid images, with iconography providing key information. The Sidekick utilizes simplified 3 button controls that allow for easy manipulation in the field and offers one-touch in-unit video recording to capture all of your experiences.
Features
Multiple Color Palettes
Intuitive 3-Button Control
1.5h Runtime on 1 x CR123A Battery, 5.5h on 2 Batteries with Included Battery Extender
Image Detail Enhancement
Dovetail Mini-Rail Included for Helmet Mounting (with Optional Mount)
Works with Rayvn Group Modular Bridge Mount for Helmet-Mounting with PVS-14, MNVD, or Second Sidekick (sold separately)
Ability to Shift Thermal Image to Collimate Sidekick Image with NVD when Bridged
Video Recording & Image Capture
USB Video Stream
USB-C Interface for External Devices
Compass
Battery Status Indicator
ULTEM Composite Body and Ergonomic Design
Designed and Assembled in the USA from U.S. and Global Component
Package Includes
Sidekick 640 Mini Thermal Monocular
2 x CR123A Battery
USB-C Cable
Lens Cloth
Soft Case
Product Manual