Install TLR7 Sub on Glock 43X/48 in 5 Steps

By Shop Tactical Gear & Holsters丨Guerrilla Tactical | Published: 2026-10-23

Category: How-to Guides

Learn how to install a Streamlight TLR7 Sub on a Glock 43X or 48. Step-by-step guide with common mistakes to avoid for a secure fit.

Quick answer

Installing a Streamlight TLR7 Sub on a Glock 43X or 48 takes about five minutes with no tools. The key is selecting the correct key for your rail and tightening the clamp evenly.

Why the TLR7 Sub fits the Glock 43X and 48

The Streamlight TLR7 Sub is designed for subcompact handguns with a proprietary rail. The Glock 43X and 48 both use a Glock-style rail, which the TLR7 Sub accommodates with the included keys. This light sits flush with the muzzle on a 43X and extends just past it on a 48, giving you a compact, low-profile weapon light that doesn't add bulk.

What you need before starting

You need the TLR7 Sub, the correct rail key (Glock key is typically marked "G"), and a flat surface to work on. The light comes with a CR123A battery installed, but you may want to test it before mounting. No tools are required—the clamp system is tool-less.

Step-by-step installation

1. Remove the battery and test fit: Remove the battery drawer by pressing the release tab on the back of the light. Take out the CR123A battery. Slide the light onto the rail from the front of the trigger guard until it clicks. If it doesn't seat fully, you may need a different key. Common mistake: forcing the light on with the wrong key can damage the rail. Check that the key matches your Glock's rail slot.
2. Select and install the correct key: The TLR7 Sub includes multiple keys. For a Glock 43X or 48, use the key marked "G" (Glock). Insert it into the slot on the clamp and push it in until it snaps into place. The key should sit flush. Checkpoint: the key must click in fully. A loose key will cause the light to shift under recoil.
3. Attach the light to the rail: With the key installed, slide the light onto the rail from front to back. The clamp should engage the rail groove. Push until you hear a click, indicating the light is seated. Do not force it. Common mistake: sliding the light on at an angle can strip the rail. Keep it straight and level.
4. Tighten the clamp: Turn the thumbscrew on the clamp clockwise until snug. Do not overtighten—the light should not move when you push on it, but you should still be able to turn the thumbscrew by hand. Use the tool-less design; no screwdriver needed. Checkpoint: after tightening, try to wiggle the light. If it moves, tighten a quarter turn more. If it won't budge, it's too tight—back off slightly.
5. Reinstall the battery and test: Reinsert the CR123A battery with the positive end facing forward (toward the lens). Slide the battery drawer back in until it clicks. Press the paddle switches to test: momentary on, constant on, and off. Ensure the light cycles through all modes. Common mistake: inserting the battery backward. The light won't turn on, but no damage occurs. Double-check orientation if it doesn't power up.

Product facts

TLR7 Sub - For Glock: The Streamlight TLR7 Sub securely attaches to select Glock sub compact hand guns. It's specifically built for the Glock 43X and 48 rail, so you get a secure fit without adapters.
TLR7 Sub - For Glock