Some spark plugs have the word SOLID in their name which means the terminal type is solid as opposed to removable nut

Yamaha YZ450F Glide Plate

The boots have been developed to offer excellent performance while riding

while the square bead wires improve casing rigidity

AXP Racing - Skid Plate PHD (6mm Thick) for Gas-Gas EC450F-EC500F-MC450F-ES500-EW500F-EX450F 2024-2025 Options:Black Some spark plugs have theDesigned for motocross, super cross and classic enduro use Weight: 0. 8kg 6mm thick HDPE plastic Protects the subframe, the engine, the crankcase from projections Plastic is 30 to 40% lighter than aluminum HDPE does not generate vibration, does not undergo deformation and absorbs impacts