1 Gang 2-Way Intelligent Dimmer 10-200W (5-150W LED) - Polished Brass Screwless

The Knightsbridge SF2191PB is a 1-gang 2-way intelligent dimmer rated for 10-200W resistive loads or 5-150W LED loads, fitted behind a polished brass screwless faceplate with a matching brass rotary dimmer cap. The dimmer automatically detects lamp type and switches between trailing-edge mode (for LEDs, CFLs, electronic transformers) and leading-edge mode (for resistive and inductive loads including incandescent bulbs and wire-wound transformers).

Designed for two-way switching installations where a single lighting circuit is controlled from two locations, the dimmer fits standard 25mm minimum back boxes and uses a screwless cover plate that clips onto a separate steel sub-frame. The rotary push-on/off action allows the user to press the cap to switch the circuit on or off, or rotate it to dim up and down. A front-facing control knob behind the cover plate allows trimming (setting minimum and maximum brightness), resetting to factory defaults, and manual mode switching without removing the faceplate.

The polished brass finish provides a warm metallic accent that pairs with traditional, classical and warm-toned interiors. The dimmer includes overload protection, overheat protection and an inrush current limiter (ICL) to prevent damage from LED lamp power-on surges. The unit ships pre-set to trailing-edge mode, which suits most dimmable LED and CFL installations. For best performance, use the dimmer with a single lamp type and wattage per circuit — mixing different brands, technologies or wattages on the same dimmer can cause flickering or erratic dimming behaviour.

Product Specification Sheet

What's the difference between trailing-edge and leading-edge modes?

Trailing-edge mode suits dimmable LED bulbs, CFLs and electronic transformers. Leading-edge mode suits traditional incandescent bulbs, halogen bulbs and wire-wound transformers. This dimmer auto-detects the lamp type and switches mode accordingly, but you can also manually override via the front control knob if needed.

Can I use this with mixed bulb types on the same circuit?

No. Mixing different lamp technologies, brands or wattages on the same dimmer can cause flickering, buzzing or erratic dimming. Use the same bulb type and model across all fittings controlled by this dimmer for reliable performance.

What back box depth is required?

A 25mm minimum back box depth is needed for safe installation. The screwless cover plate adds 4.3mm of projection from the wall once fitted, with 21.3mm recessed behind the wall surface.

How do I adjust the minimum and maximum brightness?

Remove the screwless cover plate to access the front-facing control knob. Use the knob to set the minimum dim level (trim function) and maximum brightness level. Full instructions are in the Product Specification Sheet linked under Downloads.