Tempest Spark Plug UREM40E

Thread size: 18 mm
Reach: 1/2"/1.27 cm
Shielded Threading: 5/8" - 24
Standard Electrode: Two Prong
Plug Gap: .016"-.021"/0.41-0.53 mm

Aviation Spark Plugs 
With the most automated manufacturing processes and the most innovative spark plug in the aviation industry. Made in USA. 

High Conductivity Copper 
Core Center Electrode 
copper, co-extruded inside a nickel alloy sleeve ensures outstanding heat and electrical conductivity while the nickel sleeve offers high resistance to corrosive combustion gases.

High Alumina Ceramic Insulator
high mechanical strength, superior dielectric properties, proprietary protective glaze, provides high performance to conquer severe operational conditions. "Clean Collar" massive electrode "V" tip focuses heat to reduce fouling and enhance heat range control. 

Proprietary Glass Center Seal 
21st century 'fired in' resistor replaces the multipart screw, spring, carbon pile stack up used in competitive plugs and known to suffer from resistance value instability that can cause misfires, wasted fuel, engine roughness. 

Nickel Finish
environmentally preferable electrolytic nickel provides outstanding durable finish, superior corrosion protection, and extreme wear resistance.

Nickel Ground Electrodes 
aviation grade nickel electrode design focuses on minimizing sparking voltage requirements while maintaining specification gaps to ensure large, stable 'flame kernels' for on-time ignition and complete combustion. 

Vacuum Infused Center Electrode
proprietary, vacuum infusion process seals electrode/insulator gap providing stable heat range and superior center electrode cooling (heat flow to the insulator). 

Hot-Lock Assembly
intense pressure and heat create positive, zero-leakage, shrunk in seal between insulator and shell to contain the hot, high pressure combustion cycle gases. 

Harness Wire Contact
smooth, uninterrupted, oxide treated spring contact surface offers enhanced corrosion resistance, is chemically bonded to the fired-in resistor providing the ultimate harness/spark plug termination integrity and energy transfer.