Difference between N3 and N4 Hot: N3 is a hot head, and N4 is a cold head; the start temperature of N3 is a littler higher than N4, so N3 is more suitable for Winter use, N4 is suitable for Summer.
Longer Lasting Element, For Vehicles with 4c Engines 5% - 40% Nitro Fuels
5 PCS N4 Hot Glow plug: Hot 70117 Platinum/Iridium Super Spark Glow Plug for Traxas T-maxx Kyosho HSP1 HPI Redcat 1/8 1/10 RC Nitro Engines Car Truck Buggy
Notice : Ignition time of N3 should not exceed 10s, N4 not exceed 15s, to avoid damaged the hot spark plugs. After the engine is started, unplug the igniter, the engine speed drops or stalls, eliminate the cause of rich oil, and replace the glow plug in time.