This is a NGK Spark Plug BPR6HS-10 Stock # 2633 Harley Davidson Sportster, Roadster 1000.  See more information below about the machines and years.  Free shipping within the 48 continental US states only.  Questions are always welcome.  Thanks so much.

Features
Trivalent metal plating provides superior anti-corrosion and anti-seizing properties
Pure alumina silicate ceramic insulator, provides superior strength and better heat transfer
Triple seals prevent leakage
Corrugated ribs prevent flashover
Copper core aids in heat removal

Specs
Riding Style Street
Spark Gap 1 mm / 0.039" / 1 mm (0.039")
Product Name Spark Plug
Style Standard
Center Electrode Projection Projected
Hex Size 20.6 mm
Units Each
Ground Electrode Shape Standard
Center Electrode Type Standard
Electrode Tip Material Nickel Alloy
Ground Electrode Configuration Single
Thread Reach 20.6 mm
Type Resistor
Electrical Resistance 5k Ohms
Heat Range 6
Model BPR6HS-10
Terminal Configuration Removable Nut

1983-1985 Harley-Davidson Sportster 1000 XLX
1979-1985 Harley-Davidson Sportster 1000 XLH
1979-1985 Harley-Davidson Roadster 1000 XLS
1979 Harley-Davidson Sportster 1000 XLCH