Marty Airsoft reviews the iRay Saim SCP 19W which is a lightweight, compact and budget thermal imaging sight, though the "budget" description can be subjective as this costs over a thousand quid. The Saim SCP19 has 19mm lens to capture thermal signatures; the FOV measures 9.2 x 6.9 degrees; and it comes with a 4x digital zoom to get additional details.