Just found this old video I made last year after I'd fitted a Laser Interceptor system to the front and rear of my ML merc...
I shot this to prove to a few doubters about how well the LI worked against 2 of the UK's most popular laser guns, the Prolaser II and Ultralyte 20/20 (updated version of the Marksman used in laser vans)
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As a guide, I'd previously fitted 2 Laser Pro Park heads to the front of this ML and got speed readings at around 250ft average (front only, heads too deep to fit on the rear). I ended up with 3 heads up front to achieve the same result as the 2 heads of the LI.
Hope this was helpful for folks.