Lots of shooters out there think they need a laser and light for their defensive guns but don't want to break the bank to have that capability; that's the niche the Streamlight TLR-4 is trying to fill. Here's what I've found in my testing.
-Cost. The light can be had for around $120 shipped.
-Uses one 3V CR2 lithium battery.
-Fits on most modern rail systems and has a couple different inserts for secure fitting
-It handles recoil well. I've used the light on my G20 with hot ammo as well as on an AK with 0 issues from the recoil
-Toggle switch allows either laser only, light only, or both on function modes.
-110 lumen output. It's a nice white light with a good peripheral cone.
-Relatively small (2.7'' long) which a lot of guys like for use on medium frame handguns (G19/P229/ect..).
-Lightweight. Weighs 2.8oz with batteries.
-1.5 hour constant run time.
-Uses a common rocker system for both momentary on and constant on operation.
-Laser is windage/elevation adjustable for zeroing the laser.
-It is secured with a clip (see video for explanation/demonstration) to mount to a rail.
-It's not as bright as some lights on the market.
It's a good light for those on a budget that want a light they can depend on backed up by a good warranty should an issue ever arise. Is it the brightest light on the market? Nope. But it's probably bright enough for most shooters needs and certainly bright enough to momentarily disorient an attacker if shined in their eyes.
Here's a video showing the light in use on several guns, a comparison with the 300 lumen TLR1 and a 104 lumen LED Maglite, followed by a demonstration of how it mounts and how to operate the light:
Streamlight TLR4 HD Video Review Link