NGK spark plugs. Used on an RB20DET. Used to check the heat range difference. Used for less than 2500km. Since they were installed in an engine and used, there is some carbon buildup. The tips have not been brushed, and they are stored as they were removed. The plugs themselves were purchased from a major auto parts store, not a generic brand. The original box for 2 plugs is crushed, but the original plug protection tubes are used. The 4-pack is in good condition. If you would like additional photos, please comment. Shipping will be via air-packing, Yu-Packet, Yu-Packet Post, etc. Thank you.