The light reportedly produces 630 lumens of light. I don’t have a laboratory facility so I can’t measure that but I can tell you that it’s DAMN bright. I also can’t measure the exact pace/frequency of the strobe mode but I can tell you that it is disorienting.
The TLR-1 HL is equipped with a universal/picatinny rail clamp mount that is both spring-loaded AND screw on. If the screw is loose, the spring pressure helps to keep the light in place. For mounting the light, the spring pressure makes the job easy. Loosen the screw sufficiently to get the clamp sides over and onto the rail while you’re holding in the screw, let the spring pressure grab the clamp, tighten down the screw.
I found one mention of MSRP online and it wasn’t from the Streamlight website. That “mention” was in the $250 range. However, after Googling “Streamlight TLR-1 HL” I got several returns from sites selling this light for below $150 and a couple below $140. Given the functionality and light output I think that’s a pretty good price.