Out here in the country, it always amazes me how dark the night really is compared to what folks who live in town experience with all the ambient light shining around them. We can see the glow surround the air and sky above the nearest large town ten miles away from us, but it is pitch black around here unless the sky is clear and the moon is shining bright. A good light is always handy out here.
When we first started looking for weapon lights for our handguns a couple of years ago, we read a lot of the reviews and tried a few guns with lights our friends had. There are a lot of good brands and lights out there, but in the end we chose the Streamlight TLR-1s Weapon Light for our home protection guns due to reputation, ease of use for me and the gals, quality, and cost.
My first introduction to Streamlight products were the rechargeable, full-size flashlights we had in our police cruisers back in the 1980s. Their were well built, fairly bright for the technology of the time, and if you didn't have time to get in your daily workout, your could use a couple of Streamlights instead of ten-pound barbells. In comparison, the TLR-1s is fairly light at around four ounces and makes muzzle flip on our Ruger SR9's seem almost non-existent.
Powered by two lithium CR123A batteries, Streamlight claims up to 160 lumens of light for two and a half hours. We've had the lights on continuously for about 30-40 minutes during night-time practice. We've put 350 rounds through a Ruger SR9 in a single session of shooting with the light on without any problems. You will find that after shooting with the light on for that amount of time the unit gets pretty hot, but we've had no problems due to the heat.
While the clamping screws are tightened down pretty good and have never come loose, you might consider some Loctite if you plan to leave the light on the gun. We've experienced none of the polymer frame "pinching" problems some have reported with their weapon lights on other guns. Streamlight includes "keys" for mounting the lights to various firearms' rails. The Glock key works for the Ruger SR9 and SR9c, positioning the TLR-1s just right for us.
When you hear something at the door at two o'clock in the morning, the switch on the light is ambidextrous and easy to reach with your trigger finger. For right-handed folks, you just flip it down for continuous light or flip it up for momentary light. If you do a quick double-flip-up on the switch, you get a bright strobe effect to disorient your intruders. We don't really train to use the double-flip-up on the switch to get the strobe effect. I'm concerned it's a lot of fine motor skills to use in a stressful situation and so far neither John Travolta or the Bee Gees have tried to break into the house or barn.
We now have five of the Streamlight TLR-1s Weapon Lights in the family. With a couple of years experience putting them through the paces in heat, humidity, rain, cold, and snow... we've been very pleased so far. We still have our Surefires and Maglites around (due to an undiagnosed flashlight addiction), but the weapon lights free up your hands compared with holding a flashlight in one hand the the gun in the other. Just remember for safety's sake, you're pointing your gun at whatever you are pointing your weapon light at.
So for things that go bump in the night, you might consider mounting up the Streamlight TLR-1s Weapon Light.