--- product_id: 7531859 title: "Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red" brand: "calterm" price: "£26.89" currency: GBP in_stock: true category: "Calterm" url: https://www.desertcart.co.uk/products/7531859-calterm-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity store_origin: GB region: United Kingdom --- # Adjustable sensitivity dial Rugged ABS housing for durability Dual LED firing & power indicators Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red **Brand:** calterm **Price:** £26.89 **Availability:** ✅ In Stock ## Summary > ⚡ Never miss a spark—ignite your diagnostics with Tru-Spark precision! ## Quick Answers - **What is this?** Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red by calterm - **How much does it cost?** £26.89 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/7531859-calterm-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity) ## Best For - calterm enthusiasts ## Why This Product - Trusted calterm brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Built to Endure:** High-impact ABS casing resists oil and withstands tough shop environments—your reliable work companion. - • **Instant Visual Feedback:** Green LED confirms power; red LED pulses with each spark, so you never miss a firing event. - • **Universal Compatibility:** Seamlessly tests both DIS and conventional ignition systems, making it a versatile must-have tool. - • **Pocket-Ready Convenience:** Compact design with clip-on activation keeps it handy and ready for on-the-go troubleshooting. - • **Precision Sensitivity Control:** Exclusive dial isolates specific plug wires, eliminating false signals for pinpoint diagnostics. ## Overview The Calterm 66331 Tru-Spark Ignition Firing LED Indicator is a compact, battery-powered tester designed for quick, accurate detection of secondary voltage in DIS and conventional ignition systems. Featuring an exclusive adjustable sensitivity dial, dual green/red LEDs for power and spark indication, and a rugged ABS housing, it ensures reliable performance in demanding automotive and powersports environments. Ideal for professionals and DIYers alike, it helps prevent costly service calls by enabling precise ignition troubleshooting. ## Description Testing equipment can be put to good use ensuring that electrical equipment is properly installed and safe to operate. Faulty installations can be lethal; the condition of electrical installations can be established when contractors use test equipment. Calterm is please to offer an innovative full feature line of test equipment designed to make electrical work faster and safer. Quickly and accurately test DIS and other ignition systems for the presence of secondary voltage without piercing or removing spark plug wires. Great for troubleshooting 'no-starts'. ## Features - SENSITIVITY ADJUSTMENT DIAL is a Calterm EXCLUSIVE feature that allows isolation of a specific plug wire and eliminates false signals from wires routed in close proximity. - Green LED indicates that the tester and batteries are operating properly. - Red LED flashes each time voltage is released from the coil through the spark plug wire. - Rugged high impact ABS housing resists oil and endures shop conditions. - Works with DIS and conventional ignition systems. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B000JFHMPC | | Best Sellers Rank | #193,732 in Automotive ( See Top 100 in Automotive ) #177 in Powersports Ignition Coils | | Brand | Calterm | | Brand Name | Calterm | | Color | Green,Red | | Compatible Devices | Vehicles with DIS or conventional ignition systems | | Customer Reviews | 4.2 out of 5 stars 370 Reviews | | Global Trade Identification Number | 00046494020230 | | Item Dimensions | 2.2 x 5.9 x 1.4 inches | | Item Type Name | LED Indicator | | Item dimensions L x W x H | 2.2 x 5.9 x 1.4 inches | | Manufacturer | Calterm | | Measurement Type | Voltage | | Model | 66331 | | Number of Items | 1 | | Part Number | 66331 | | Power Source | Battery Powered | | Specification Met | CE, ETL, RoHS, UL | | Style | Adjustable | | Style Name | Adjustable | | UPC | 971473127474 046494020230 521227771189 956257381846 | | Unit Count | 1 Count | ## Product Details - **Brand:** Calterm - **Color:** Green,Red - **Item dimensions L x W x H:** 2.2 x 5.9 x 1.4 inches - **Power Source:** Battery Powered - **Style:** Adjustable ## Images ![Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Image 1](https://m.media-amazon.com/images/I/71R5oKpSNAL.jpg) ![Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Image 2](https://m.media-amazon.com/images/I/71e2wcEolPL.jpg) ![Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Image 3](https://m.media-amazon.com/images/I/71JaUL5uNJL.jpg) ![Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Image 4](https://m.media-amazon.com/images/I/819anuVXdGL.jpg) ## Questions & Answers **Q: Does clamp on?** A: Hi, no it's not for clamping on, it's for detecting for a spark and so you just touch it on the ht lead **Q: does it work on small engine 4-cycle, 12V** A: Our Service dept use this all the time on small engines. You do have to properly adjust the dial on the unit for small engines. We use as a quick test. **Q: does this actually detect if the plug wire is pulled loose from the plug itself?** A: Probably not, but a good visual inspection should. I use it to narrow down suspect cylinders that have a misfire such as a defective coil or wire. I have also found plugs that arc inside the plug boots. **Q: Will this work on fuel injectors ?** A: No- Just ignitions. Fuel injectors are low voltage. ## Frequently Bought Together - Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Lisle 19380 Spark Tester - allsun Automotive Spark Ignition Tester 6-24V Pen Engine Indicator Spark Plug Car Wires Coils Diagnostic Tool Auto Voltage Cable Detector Small Engine Tools --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/7531859-calterm-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity](https://www.desertcart.co.uk/products/7531859-calterm-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-10-28*