The Festool Light Module LM-RTS for RTS/RTSC/ETS125/ETSC125 Sanders (578836) is a clip-on LED work light designed for one job: showing you exactly what your sander is doing to the surface in front of you. This is a sanding accessory light designed for spotting surface defects — scratches, swirl marks, and uneven sanding patterns — while you're still sanding, not after the finish goes on and it's too late to fix. It attaches directly to compatible Festool RTS and ETS orbital sanders and runs on its own rechargeable battery, independent of the sander's power.

The light casts a low, raking beam across the work surface right where the pad is cutting, which is the angle that actually reveals texture. Two brightness levels let you dial in the right amount of light for the job — full brightness for well-lit shop conditions or dimmed for glare-sensitive surfaces like glossy or dark-stained wood, where too much light can wash out the very defects you're trying to see. A vibration sensor handles the on/off switching automatically: start sanding and the light comes on, stop and it shuts off, so there's no separate switch to remember or forget.

Inside is a 60-LED COB array putting out 50 lumens on the low setting and 150 lumens on high, at a 5000 Kelvin color temperature that renders surface detail clearly without a yellow or blue cast. Power comes from a built-in lithium-polymer battery good for up to 250 minutes on the low setting or 150 minutes on high, recharged in about 80 minutes over USB-C. The housing carries an IP54 rating, so dust and light moisture on a jobsite or in a dusty shop won't take it out of service.

Mounting is tool-free — the module clips onto the sander's housing and stays put through normal sanding vibration, then pops off just as easily when you want to move it to another compatible sander or set it aside. This version fits the Festool RTS 400, RTSC 400, ETS 125, and ETSC 125 sanders (2017 and newer); Festool also sells matching light modules sized for other sander families, so make sure you're ordering the version cut for the sander you actually own.

This is a smart add-on for anyone doing finish sanding where surface quality is the whole point — furniture builders, cabinet makers, trim carpenters, and finish-focused DIYers working under shop lighting that doesn't always show flaws until the stain or clear coat hits the wood. If you've ever sanded a panel, moved it under better light, and found swirl marks you missed, this module is built to stop that from happening.

The Cheapest Insurance Against Redoing a Finish Sand

The Festool Light Module LM-RTS turns your RTS or ETS sander into a tool that shows you its own work instead of hiding flaws under bad shop lighting.

• Who it's for: Anyone finish-sanding furniture, cabinetry, or trim on a compatible Festool RTS or ETS sander who's tired of finding swirl marks after the finish is already on.
• Why it stands out: Automatic vibration-triggered on/off and a two-level brightness setting mean it's genuinely hands-free — no switch to flip, no glare to fight.
• Worth knowing: This version fits the RTS 400, RTSC 400, ETS 125, and ETSC 125 sanders (2017+); Festool sells other light modules for its other sander families, so check your sander model before ordering.

• Does this work with any Festool sander? No. The LM-RTS is built specifically for the RTS 400, RTSC 400, ETS 125, and ETSC 125 sanders made in 2017 or later.
• Does it need to be plugged into the sander? No. It runs on its own built-in rechargeable battery and recharges separately over USB-C, so it doesn't draw power from the sander itself.
• How does the light know when to turn on? It uses vibration detection — the light switches on automatically once sanding starts and shuts off when the sander stops.
• How long does the battery last on a charge? Up to 250 minutes on the low brightness setting or 150 minutes on high, with a full recharge taking about 80 minutes.